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Hatcheries nationwide suffer from unexplained acute production failures, termed crashes. The microbiota of oysters relates to larval health with previous studies showing that some bacterial species have positive and others negative effects on oyster health. To investigate microbial correlates of crashes, we collected samples from every batch of oyster larvae (Crassostrea virginica) produced by the Horn Point Laboratory Oyster Hatchery since 2021 and analyzed the microbiota of 15 of those batches over their duration in the hatchery, from age of 3 to 5 days until either harvest or complete die off of the batch. Across events, die-offs generally became evident at or after six days of age. We found that the microbiota of oyster larvae appears to respond to die-off events with crashed batches having fundamentally different microbiota than good batches at age 7 to 9 and 9 to 12 days. Crashed batches were often taken over by microeukaryotes and bacterial taxa from the Protobacteria and Bacteroidetes phyla. However, this presumably opportunistic community differed between batches. Observed Vibrio species level groups did not appear to be oyster pathogens and appeared to respond to, rather than precede, crashes. The microbiota of 3 to 5 day old larvae were statistically related to whether a die-off occurred later in the larval batches' life, only when the taxa were first agglomerated to family level. The detection of two microbial species not previously known to associate with oysters, along with an increased presence of Dinophyceae, predominantly the toxin-producing Gyrodinium jinhaense, in 3 to 5 day old oyster larvae was statistically linked with subsequent batch crashes. This study suggests that the health of larval oysters shapes their microbiome. Conversely, it provides hints that the microbiome of larvae, and perhaps harmful algae, may drive hatchery crashes. [ABSTRACT FROM AUTHOR]

Objective: Poor milt yield via strip‐spawning in male Sauger Sander canadensis limits the production of saugeye (female Walleye S. vitreus × male Sauger) by the Ohio Division of Wildlife. Compared to strip‐spawning, collecting sperm via testicular harvest offers several advantages that increase production efficiency through enhanced sperm yield (e.g., requires fewer broodfish, allows higher sperm application rates, and increases fertilization rates). The benefits of testicular harvest have been demonstrated experimentally in Sauger but not at a production scale. In this study, I validated the large‐scale efficacy of testicular harvest in Sauger for saugeye production. Methods: I collected sperm from male Sauger by using either testicular harvest (42 fish) or strip‐spawning (222 fish), diluted samples with extender, and combined samples to create 9‐mL sperm pools (n = 21 for testicular harvest; n = 39 for strip‐spawning). I compared sperm quantity, sperm motility, and production attributes (broodstock requirements, sperm application rates, and expected fertilization) between testicular harvest and strip‐spawning collection methods. Result: Both collection methods resulted in high‐quality sperm. Testicular harvest doubled the sperm yield (total number of sperm) per 9‐mL pool despite using only 2 fish/pool, while strip‐spawning required 5–7 fish/pool. Through this enhanced yield, testicular harvest produced enough sperm to fertilize 317 L of eggs (1.06 mL/L) by using 80% fewer males than strip‐spawning. Further, sperm application increased fourfold using testicular harvest (4.23 mL/L) while still requiring 30–40% fewer fish than are currently used to meet production. Adopting testicular harvest for saugeye production in 2023 increased broodstock sperm yield, allowed greater sperm application rates, reduced Sauger broodstock needs, and increased saugeye hatching rates (15–20% increase). Conclusion: Testicular harvest provides an efficient approach for sperm collection during large‐scale production in fish species that produce small quantities of sperm. Impact statementHarvesting Sauger sperm via testicular harvest substantially increased the sperm yield compared to strip‐spawning and in turn reduced broodstock requirements while still allowing higher sperm application rates during fertilization. [ABSTRACT FROM AUTHOR]

Fish diseases and inbreeding are among the factors limiting fish production. The present study aimed to assess the effect of biosecurity measures implementation levels (BMIL) and genetic type on epidemiological and zootechnical characteristics in hatcheries, in order to contribute to healthy and sustainable fish farming. Crosses (Beninese males x Cameroonian females and Cameroonian males x Cameroonian females) were carried out between two strains of domestic broodstock. The epidemiozootechnical characteristics evaluated (mortality rate, prevalence of pathologies, fertilization rate, hatching rate, productivity and economic profitability) were subjected to descriptive statistics, Student's t-test and two-factor analysis of variance. The resulting larvae were distributed in duplicate to three hatcheries, in which biosecurity measures were selectively applied to obtain the desired BMILs (low, medium and high) for each hatchery. As results, the highest mortality rate (100%) was recorded in the hatchery where the BMIL was low, then decreased significantly in crossbreds for both medium and high BMILs. Apart from fish deformities, the prevalence of other pathologies (anorexia and abnormal swimming) decreased significantly with BMIL. The prevalence of pathologies was about two times significantly higher for the pure strain than for the crossbreds. Fertilization and hatching rates dropped significantly with BMIL, with hybrid cross recording the highest values. Productivity and economic profitability increased significantly with BMIL. Values were 16 and 2 times higher in crossbreds than in the pure strain for medium and high BMIL respectively. Overall, the increase in BMIL and the use of genetic types have improved the epidemio-zootechnical characteristics of Clarias gariepinus in hatcheries. Fish farmers need to focus on biosecurity measures and use crossbreds from the Cameroon x Benin cross for optimum production. [ABSTRACT FROM AUTHOR]

Abstract Background Salmon aquaculture involves freshwater and seawater phases. Recently there has been an increase in multifactorial gill health challenges during the seawater phase which has led to an urgent need to understand the gill microbiome. There is a lack of understanding on what drives the composition of the gill microbiome, and the influence the freshwater stage has on its long-term composition. We characterise the gill microbiome from seven cohorts of Atlantic salmon raised in six different freshwater operational systems—recirculating aquaculture system (RAS), flowthrough (FT) and loch-based system, prior to and after transfer to seven seawater farms, over two different input seasons, S0 (2018) and S1 (2019). Results Using the V1-V2 region of the 16S rRNA gene, we produced amplicon libraries absent of host contamination. We showed that hatchery system influenced the gill microbiome (PERMAOVA R2 = 0.226, p

Abstract Hatcheries, where eggs from multiple breeder farms are incubated and hatched before being sent to different broiler farms, represent a nexus point in the commercial production of broilers in the United States. Considering all downstream microbial quality and safety aspects of broiler production (live production, processing, consumer use) can be potentially affected by the hatchery, a better understanding of microbial ecology within commercial hatcheries is essential. Therefore, a commercial broiler hatchery was biomapped using 16S rRNA amplicon-based microbiome analyses of four sample type categories (Air, Egg, Water, Facility) across five different places in the pre-hatch, hatch, and post-hatch areas. While distinct microbiota were found for each sample type category and hatchery area, microbial community analyses revealed that Egg microbiota trended towards clustering with the facility-related samples when moving from the prehatch to post-hatch areas, highlighting the potential effect of the hatchery environment in shaping the pre-harvest broiler-related microbiota. Prevalence analyses revealed 20 ASVs (Core20) present in the core microbiota of all sample types and areas, with each ASV possessing a unique distribution throughout the hatchery. Interestingly, three Enterobacteriaceae ASVs were in the Core20, including Salmonella. Subsequent analyses showed that Salmonella, while a minor prehatch and hatch Core20ASV, dominated the Enterobacteriaceae niche and total microbiota in the chick pad feces in the post-hatch area of the hatchery, and the presence of this Salmonella ASV in the post-hatch feces was associated with swabs of breakroom tables. These findings highlight the complexity of commercial hatchery microbiota, including identifying chick pad feces and breakroom tables as potentially important sampling or disinfection targets for hatchery managers to focus their Salmonella mitigation efforts to reduce loads entering live production farms.

One of the main threats to aquaculture is represented by microbial pathogens, causing mass mortality episodes in hatcheries, which result in huge economic losses. Among the many disinfection methods applied to reduce this issue, the use of chemicals and beneficial microorganisms (probiotics) seems to be the most efficient. The aim of this study is to test the efficacy of two of them: a chemical, peracetic acid (PAA), and a probiotic, Phaeobacter inhibens. Tests were run on microalgae of the species Isochrysis galbana (var T-ISO). For both remedies, the microalgae survival rate and final cell concentration (cell/mL) were monitored. PAA analysis tested six different concentrations of the chemical: 7.5 µg, 10 µg/L, 20 µg/L, 30 µg/L, 40 µg/L, and 60 µg/L. Meanwhile, P. inhibens was tested with a concentration of 104 CFU/mL. Analysis for both the remedies was conducted on a laboratory scale using glass flasks, and on an industrial scale inside photobioreactors (PBRs). Among all the treatments, the one with PAA dosed with a concentration of 60 µg/L gave the best results, as the culture reached a final density of 8.61 × 106 cell/mL. However, none of the remedies involved in the experiment harmed microalgae or their growth. The results match perfectly with the condition requested for the tested remedies: to obtain an optimal breakdown of pathogens without interfering with culture growth. These features make PAA and P. inhibens good candidates for disinfection methods in aquaculture facilities. [ABSTRACT FROM AUTHOR]

Hatcheries, where eggs from multiple breeder farms are incubated and hatched before being sent to different broiler farms, represent a nexus point in the commercial production of broilers in the United States. Considering all downstream microbial quality and safety aspects of broiler production (live production, processing, consumer use) can be potentially affected by the hatchery, a better understanding of microbial ecology within commercial hatcheries is essential. Therefore, a commercial broiler hatchery was biomapped using 16S rRNA amplicon-based microbiome analyses of four sample type categories (Air, Egg, Water, Facility) across five different places in the pre-hatch, hatch, and post-hatch areas. While distinct microbiota were found for each sample type category and hatchery area, microbial community analyses revealed that Egg microbiota trended towards clustering with the facility-related samples when moving from the prehatch to post-hatch areas, highlighting the potential effect of the hatchery environment in shaping the pre-harvest broiler-related microbiota. Prevalence analyses revealed 20 ASVs (Core20) present in the core microbiota of all sample types and areas, with each ASV possessing a unique distribution throughout the hatchery. Interestingly, three Enterobacteriaceae ASVs were in the Core20, including Salmonella. Subsequent analyses showed that Salmonella, while a minor prehatch and hatch Core20ASV, dominated the Enterobacteriaceae niche and total microbiota in the chick pad feces in the post-hatch area of the hatchery, and the presence of this Salmonella ASV in the post-hatch feces was associated with swabs of breakroom tables. These findings highlight the complexity of commercial hatchery microbiota, including identifying chick pad feces and breakroom tables as potentially important sampling or disinfection targets for hatchery managers to focus their Salmonella mitigation efforts to reduce loads entering live production farms. [ABSTRACT FROM AUTHOR]

Introduction: Seed production has experienced significant growth in Bangladesh over the last decade, driven by the increasing number of hatcheries. The hatchery segment plays a crucial role in the overall growth and development of aquaculture in the country. Understanding its structure, conduct and performance is essential for assessing its impact on the productivity and profitability of aquaculture farms. However, there is a limited number of methodologically rigorous studies focusing on the hatchery segment in Bangladesh. The study aimed to fill the gap in the exiting literature by conducting a methodologically analysis of the hatchery segment of aquaculture value chain in Bangladesh. Methods: This study was conducted in seven of the main aquaculture producing districts in southern Bangladesh. A comprehensive structured survey was conducted between May and August 2022 with 66 enterprises, including 42 carp+catfish, 16 tilapia, and 8 crustacean hatcheries. Results and discussion: The major findings and their implications are as follows. (1) The number of hatcheries increased by 15% over the past decade, with a 27% increase in fish hatcheries and a 47% decrease in crustacean hatcheries. (2) Carp and tiger shrimp were the most commonly produced fish and crustacean seeds, contributing 67% and 99% of volume and 66% and 97% of sales value, respectively. (3) The hatcheries were family-owned and operated enterprise, and generated a total 2,491 full time equivalent (FTE) jobs. (4) Hatcheries used 86% of their broodstock annually and replaced them regularly for improving quality and avoiding inbreeding. (5) 18% of hatcheries reported facing diseases and/or water quality problems, but mean economic loss was only 0.71% of seed sales value, which is a low level of loss and waste. (6) Average annual net profit margin was relatively modest, averaging 54% of the gross revenue, which suggests the existence of competitive seed production and marketing. The results showed that the hatchery segment in southern Bangladesh appears to be dynamic, well developed, efficient, and relatively competitive. [ABSTRACT FROM AUTHOR]

Hatcheries are hubs for incoming eggs and progeny flock output, making them a crucial component of the poultry production chain. This study involved performing quantitative microbiological tests in a commercial hatchery with numerous compartments, including an egg handling room, cold storeroom, setter room, hatcher room, and chick production hall. There were 150 air samples and 180 surface swabs collected in the incubator before and after disinfection over ten visits, in addition to 250 yolk sac and organ samples taken from late-dead embryos. As a result, surface swabbing could detect higher contamination levels than open-plate methods in all hatchery visits, mainly in handling eggs, cold storage, and hatcher halls. This study examines the presence of Pseudomonas aeruginosa strains in hatchery environments and dead embryos. Biochemical and PCR testing were used to identify P. aeruginosa using 16SrDNA primers at 956bp and the toxA gene at 396bp. In hatchery environmental samples, the incidence rate was 10.7%, and in dead embryos, it was 10%; therefore, maintaining good hygiene, especially in hatcheries, is essential for Pseudomonas species control. Subsequently, in this study, a virulent strain of P. aeruginosa was subjected to an in vitro test with 10 disinfectants from six chemical groups. Iodine compounds with phosphoric acids, per-acetic acid, sodium dichloroisocyanurate, and quaternary ammonium compounds (QACs) with glutaraldehyde compounds showed 100% microbial reduction even in the presence of organic matter with exposure times of 30 min. It was concluded that the most effective and cost-effective way to prevent and control infections is to use a disinfectant with sufficient concentration and exposure time in hatcheries. [ABSTRACT FROM AUTHOR]

Lumpfish are broadly used as biological sea lice removers in Norwegian salmon farming and are mostly produced in hatcheries. To date, there is little systematic documentation on the mortality causes of lumpfish in hatcheries. In the current study, data from 12 selected fish groups from four hatcheries in Norway were collected to understand the challenges and opportunities related to the categorization of mortality causes of lumpfish in hatcheries. This study indicated that a high proportion of lumpfish mortality was categorized by the hatcheries as unspecified. When specified, mortality was primarily assessed as due to fin damage. Our analyses showed that mortality categorized as fin damage correlated with the detection of infectious agents in dead fish, suggesting that mortality was due to infections rather than fin damage. It was not possible to conclude whether infection with pathogens present in the environment caused fin damage or if injuries from aggression were a gateway for pathogens. Furthermore, due to the lack of information regarding production conditions, it was not possible to assess risk factors causing eventual aggression or the presence of pathogens. This study revealed that mortality causality—the chain of events leading to death—is mainly unclear in lumpfish hatcheries because (1) mortality categorization does not focus on underlying causes and (2) there is little documentation of production conditions, making it very difficult to relate mortality rates to external factors. The present findings highlight that there are gaps in the registrations made by hatcheries and that there is an urgent need to implement standardized monitoring protocols for lumpfish hatcheries. This will help identify the causes of mortality and, therefore, allow for the implementation of proper measures that will ensure better survival. [ABSTRACT FROM AUTHOR]

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ABSTRACT The physical parameters of eggs significantly impact embryo development and hatching success. This study aimed to examine the influence of the egg shape index (SI), specific gravity (SG), weight loss (WL), and area-volume ratio (AV) on hatching eggs from brown-layer hen grandparents. A total of 7,500 eggs were randomly selected from two batches of Lohmann Brown grandparents at various ages (39, 44, 50, 58, and 66 weeks). SG was determined by flotation (1,070 to 1,090 g/L), while egg length, width, and weight were measured digitally. Each egg was tracked to determine hatching success, with unhatched eggs collected for embryonic diagnosis. Physical parameters were categorized into minor, intermediate, and major groups, based on viability frequency; and embryonic mortality was analyzed using the chi-square test and odds ratio (OR). The study found a lower probability of embryo death in eggs with intermediate SI (75.1% to 79%) and AV (1.01 cm²/cm³ to 1.04 cm²/cm³). No significant differences were observed between SG and WL groups. SI proved to be a reliable parameter for assessing egg quality and predicting hatchability.

Abstract Calcium (Ca) is an essential mineral for eggshell formation and muscle contraction, and a lack of it can result in poor egg quality and decreased egg output in laying ducks. This study aims to see how feeding the mineral Ca in a ration containing Shrimp head meal and Bilis fish head affects the laying performance and quality of hatching eggs in Mojosari ducks. A total of 105 female and 15 male Mojosari ducks, aged 78 weeks, were raised for three months and randomly divided into 15 flocks (each flock containing seven females and one male duck). There were three kinds of treatment, namely P0 (control, without mineral), P1 (ratio of Shrimp head meal and Bilis fish head 2:1 + 1% mineral), and P2 ((ratio of Shrimp head meal and Bilis fish head 1:2 + 1% mineral). The findings revealed that adding mineral Ca to feed, including Shrimp head meal and Bilis fish head, had no significant influence (P>0.05) on laying Mojosari duck performance in terms of feed intake, egg production, egg weight, egg quality, ducklings produced, and income over feed cost (IOFC). Furthermore, Ca addition in the ration did not result in substantial increases (P>0.05) in fertility, hatchability, or egg size characteristics. Based on the findings of this study, feeding ducks with shrimp head meal and Bilis fish head can be used as an alternate calcium-free feed formulation.

Poultry-associated salmonellosis results in significant costs to poultry producers and consumers. Given the vertically integrated nature of the United States poultry industry, a better understanding of Salmonella ecology throughout all levels of poultry production is essential. One nexus point is the hatchery, where eggs from multiple broiler breeder farms are incubated and hatched, with the chicks being sent to numerous farms; therefore, the hatchery represents an ideal area to understand preharvest Salmonella ecology and flow. To achieve this, a commercial broiler hatchery was biomapped, focusing on Salmonella prevalence and serotype diversity among four major sample type categories (Air, Egg, Water, Facility) across five different places in the prehatch, hatch, and posthatch areas. Following two sets of eggs from broiler breeder farms over two production days, the overall Salmonella prevalence was 26% (48/184). Of the positive samples, the highest prevalence was observed in swabs taken from the floor drains in the facility and transport truck (56%), as well as in the hatch and posthatch hatchery areas (50%). Kentucky (n = 17), Gaminara (n = 12), and Alachua (n = 11) were the dominant Salmonella serotypes, with serotypes of greatest outbreak concern from chickens (Enteritidis) representing only 6.25% (3/48) of all recovered Salmonella isolates. The posthatch transport area, including the underfloor reservoirs of the transport trucks, not only harbored Enteritidis but also the enrichment broths from these Salmonella-positive samples also possessed sequences matching the commercial live-attenuated vaccine Typhimurium strain according to CRISPR SeroSeq analyses. These findings highlight the complex diversity of commercial hatchery Salmonella populations, including identifying facility floor drains and transport trucks as potentially important critical control points for hatchery managers to focus their Salmonella mitigation efforts to reduce loads and serotypes entering live production farms.

Hatcheries nationwide suffer from unexplained acute production failures, termed crashes. The microbiota of oysters relates to larval health with previous studies showing that some bacterial species have positive and others negative effects on oyster health. To investigate microbial correlates of crashes, we collected samples from every batch of oyster larvae (Crassostrea virginica) produced by the Horn Point Laboratory Oyster Hatchery since 2021 and analyzed the microbiota of 15 of those batches over their duration in the hatchery, from age of 3 to 5 days until either harvest or complete die off of the batch. Across events, die-offs generally became evident at or after six days of age. We found that the microbiota of oyster larvae appears to respond to die-off events with crashed batches having fundamentally different microbiota than good batches at age 7 to 9 and 9 to 12 days. Crashed batches were often taken over by microeukaryotes and bacterial taxa from the Protobacteria and Bacteroidetes phyla. However, this presumably opportunistic community differed between batches. Observed Vibrio species level groups did not appear to be oyster pathogens and appeared to respond to, rather than precede, crashes. The microbiota of 3 to 5 day old larvae were statistically related to whether a die-off occurred later in the larval batches’ life, only when the taxa were first agglomerated to family level. The detection of two microbial species not previously known to associate with oysters, along with an increased presence of Dinophyceae, predominantly the toxin-producing Gyrodinium jinhaense, in 3 to 5 day old oyster larvae was statistically linked with subsequent batch crashes. This study suggests that the health of larval oysters shapes their microbiome. Conversely, it provides hints that the microbiome of larvae, and perhaps harmful algae, may drive hatchery crashes.

For many imperiled species, comparisons between wild and cultured populations are invaluable for informing conservation measures, though opportunities to do so may be rare. In this study, we asked whether spawning between and among wild and cultured Delta Smelt varies in terms of behavior or resulting egg fertilization success. We conducted two laboratory experiments in which we allowed wild females to spawn with wild males (wild × wild) and cultured females to spawn with wild males (cultured × wild). Due to small sample sizes, we qualitatively compared our results to published studies of all cultured Delta Smelt (cultured × cultured). Across all three groups, Delta Smelt exhibited spawns that were similar in sequence and manner, varied widely in diel timing, and occurred predominantly between a single female and one or two males. Egg fertilization success was higher in wild × wild trials than in cultured × wild ones, but both fell within the wide range observed among cultured × cultured fish. Thus, spawning was generally similar between cultured and wild Delta Smelt, whether they were in same- or mixed-origin groups. These findings provide rare insight into the spawning behavior of wild Delta Smelt and inform ongoing conservation efforts.

Sea lice (Lepeophtheirus salmonis [Krøyer, 1838]) are a key issue for salmon aquaculture, contributing to increased mortality for both wild and farmed salmon if no action is taken. Using cleaner fish can be an effective, drug‐free treatment method, and ballan wrasse (Labrus bergylta) is a hardy wrasse species that displays cleaning behavior. With concerns about the overharvest of wild ballan wrasse, many companies farm this species, but the optimal ranges of a wide variety of rearing parameters are still unknown. This study investigated the effect of 6‐week exposure to four dissolved oxygen (DO) levels (125%, 100%, 85%, and 75% DO saturation as the percentage of air) on ballan wrasse. Survival; growth (specific growth rate, SGR); condition factor (CF); and primary (cortisol), secondary (glucose, lactate, magnesium), and tertiary stress indicators (swimming performance) were investigated. There were no differences in SGR, CF, survival, or cortisol level among the groups at the end of the 6 weeks. There was variation in the magnitude of the cortisol response to an acute stressor at the end of the 6‐week period, with the 75% DO treatment exhibiting a 3.3‐fold increase in cortisol compared to a 5.2‐fold increase in the control group (100%), which could suggest chronic stress. Relative critical swimming speed (RUcrit) was measured to investigate swimming performance once all groups were returned to 100% DO saturation. The 75% RUcrit was lower than the 100% treatment (1.7 ± 0.18 body length [BL]/s compared to 2.5 ± 0.16 BL/s). Overall, these results suggest that DO levels of 75% trigger physiological changes and therefore may negatively affect welfare. [ABSTRACT FROM AUTHOR]

Opportunistic pathogens have been associated with yield-limiting factors in bivalve hatcheries. Numerous natural compounds are being investigated for their beneficial effects and potential to enhance larval resistance without requiring antibiotics. One of those is the use of marennine, a blue pigment, originating from the diatom Haslea ostrearia, which has demonstrated a positive effect on larvae survival. The aim of this study was to highlight the protective effect of marennine on Mytilus edulis larvae during bacterial challenges in relation to a potential modification of the marennine-treated larvae microbiota. D-larvae and post-larvae were exposed for 96 h to Vibrio splendidus (106 cell mL−1) with and without mareninne (500 µg L−1). The presence of marennine increased the survival rate of D-larvae exposed to the pathogen. The molecular analysis of the larvae microbiota diversity indicated a modification in the D-larval microbiota's richness related to survival rates of larvae. Ultimately, our study sheds light on the importance of the larval microbiota in pathogen resistance during the bivalve rearing process. [ABSTRACT FROM AUTHOR]

Objective: Density‐related information for landlocked fall Chinook Salmon Oncorhynchus tshawytscha shortly after first feeding is poorly understood. This study was undertaken to determine the effects of a range of rearing densities (low, intermediate, and high) on rearing performance and survival of newly feed‐trained juvenile landlocked fall Chinook Salmon. Methods: The fish were reared for 66 days in 1.8‐m (diameter) tanks with approximate volume of 2036 L at one of three loadings of approximately 2500, 5000, or 10,000 fish/tank. Result: The initial and final densities for each of the three loadings were 0.73 and 8.93, 1.45 and 16.41, and 2.90 and 26.86 kg/m3, respectively. At the end of the study, the specific growth rates were significantly lower, total lengths were significantly shorter, and feed conversion ratios were significantly greater in the fish from the highest‐density treatment relative to the fish in the other treatments. Percentage of weight gain, final weights, and condition factor were significantly reduced in fish from the highest‐density treatment relative those at the lowest density. There were no significant differences in any growth metrics between fish that were reared at the lowest and intermediate densities. The intermediate density (5000 fish/tank) produced intermediate results that did not significantly differ from either the highest or lowest densities. Mortality was not significantly different among the density treatments. Conclusion: An initial loading of 5000 fish in 1.8‐m (diameter) circular tanks, corresponding to initial and final densities of 1.45 and 16.41 kg/m3, respectively, is recommended to minimize the detrimental effects of density on newly feeding Chinook Salmon while maximizing their production in often limited hatchery space. Impact statementThe use of intermediate tank loadings of fall Chinook Salmon in 1.8‐m (diameter) circular tanks (corresponding to initial and final densities of 1.45 and 16.41 kg/m3, respectively) minimized the detrimental effects of rearing density on newly feeding salmon while maximizing Chinook Salmon production in limited hatchery space. [ABSTRACT FROM AUTHOR]

Simple Summary: A single post-hatch oral inoculation of synbiotics, along with its continued use in diets, could be a valuable technique for enhancing industry efficiency and overall outcomes. This method could potentially lead to the earlier colonization of the gastrointestinal tract (GIT) with beneficial microbes and promote a more favorable gut microflora throughout the production cycle. Our results showed that hatchery and dietary synbiotic application have a potential beneficial impact on broiler intestinal immunity by regulating the innate immune response and improving feed conversion. Future research involving extended grow-out studies with a disease challenge would expand on the implications of the early application of synbiotics and provide additional insight into their potential field applications. This study investigated the effects of a synbiotic consisting of inulin, Enterococcus faecium, Pediococcus acidilactici, Bifidobacterium animalis, and Lactobacillus reuteri given orally to day (d)-of-hatch (DOH) broiler chicks at the hatchery and in the feed for a 21 d period. A total of 480 Cobb male broilers were randomly divided into one of four treatments using a 2 × 2 factorial design as follows: (1) control (CTRL) group receiving a gel-only oral application on DOH at the hatchery prior to transport and a non-medicated basal corn/soybean meal starter diet; (2) hatchery synbiotic (HS) receiving an oral gel containing the synbiotic (0.5 mL/bird) at the hatchery and the basal diet; (3) CTRL + dietary synbiotic at 0.5 kg/MT (DS); and (4) HS + dietary synbiotic at 0.5 kg/MT (HSDS). On d 7 and d 21, one bird per pen (eight replicate pens/group) was euthanized, and the ileum was immediately removed for qPCR analysis. Data were subjected to a 2-way ANOVA using GLM procedure (JMP Pro17). A significant diet × hatchery interaction was observed in feed conversion ratio (FCR) from d 14 to d 21 (p = 0.013) where the HS, DS, and HSDS treatments had a significantly lower FCR compared to the CTRL. However, no significant interaction effect was observed for body weight gain (BWG) or FCR during the overall experimental period. No significant interaction was observed in mRNA abundance of the evaluated genes in the ileum on d 7 and d 21. Gel application with the synbiotic significantly reduced sodium-dependent glucose cotransporter 1 (SGLT1) mRNA abundance on d 7 (p = 0.035) in comparison to birds receiving gel alone. Regardless of hatchery application, dietary synbiotic supplementation significantly reduced Toll-like receptor (TLR)2, TLR4, and interleukin (IL)-10 mRNA abundance on d 7 (p = 0.013). In conclusion, these findings showed that hatchery and dietary synbiotic application could have a potential beneficial impact on broiler intestinal immunity by regulating the TLR response, a key element of innate immunity. FCR was improved from d 14 to d 21 after synbiotic application. Future research involving extended grow-out studies with a disease challenge would expand on the implications of an early application of synbiotics. [ABSTRACT FROM AUTHOR]

The objectives of this study were to assess the effects of i) pre-incubation storage time of Pekin duck eggs on incubation parameters and ii) different levels of in ovo injection with maltodextrin on Pekin duckling weight. The study was divided into two experiments using hatching eggs of Cherry Valley SM2 hens with egg-laying ages between 31 and 40 weeks. In experiment I, 8,820 eggs were subjected to different periods of pre-incubation storage (one-seven days). For experiment II, 120 eggs weighing between 75 and 85 g were selected and inoculated with 250 µL of 0.75% saline solution with different concentrations of maltodextrin treatments (0%, 1.5%, 3.0%, and 4.5%). In relation to pre-incubation storage time, eggs stored for one day had lower hatching and hatchability rates and higher duckling mortality rates than eggs stored for longer periods (P < 0.05). In ovo injection with 3.0% maltodextrin in 0.75% saline solution significantly increased the hatching weight of Pekin ducklings (53.62 g) compared to that by other study treatments (P < 0.05). Therefore, Pekin duck eggs produced between 31 and 40 weeks of life may be stored between two and seven days without affecting hatchery productivity parameters. The hatching weight of Pekin ducks may be improved with in ovo injection with 3.0% maltodextrin in 0.75% saline solution. [ABSTRACT FROM AUTHOR]

In the current study, we investigated decreased hatchability and increased embryonic mortality in two farms of layer breeders (flocks A1 and B1) and a farm of broiler breeders (flocks C1 and C2) from Austria, which also presented discoloration of eggshells in 2% of the eggs. After conducting clinical evaluations and the approval that the feed operator was common for flocks A1 and B1, and C1 and C2, it was decided to investigate the feed. Our findings revealed that the feed contained levels of nicarbazin and narasin up to five and 14 times, respectively, above the maximum limits allowed by the European Union for nontarget species. On the other hand, there were no significant abnormalities in vitamin levels, which were also described as the etiology of the noticed abnormalities. Switching to a noncontaminated feed resulted in the clinical signs and production parameters returning to expected ranges. This report emphasizes the significance of considering feed contamination by nicarbazin and narasin as a potential cause of hatchery losses in nontarget species, even in the absence of other clinical signs. Reporte de caso- Pérdidas en la eclosión de parvadas de reproductoras ponedoras y pollos de engorde debido a la contaminación del alimento con nicarbazina y narasina: Reporte de un caso. En el presente estudio, se investigó la disminución de la incubabilidad y el aumento de la mortalidad embrionaria en dos granjas de reproductoras ponedoras (parvadas A1 y B1) y una granja de reproductoras de pollos de engorde (parvadas C1 y C2) de Austria, que también presentaron decoloración del cascarón en el 2% de los huevos. Luego de realizar evaluaciones clínicas y la aprobación de que el operador de alimento era común para las parvadas A1 y B1, y C1 y C2, se decidió investigar el alimento. Nuestros hallazgos revelaron que el alimento contenía niveles de nicarbazina y narasina de hasta cinco y 14 veces, respectivamente, por encima de los límites máximos permitidos por la Unión Europea para especies no objetivo. Por otro lado, no se observaron anomalías significativas en los niveles de vitaminas, lo que también se describió como la etiología de las anomalías observadas. El cambio a un alimento no contaminado provocó que los signos clínicos y los parámetros de producción regresaran a los rangos esperados. Este informe enfatiza la importancia de considerar la contaminación del alimento por nicarbazina y narasina como una causa potencial de pérdidas en la eclosión de especies no objetivo, incluso en ausencia de otros signos clínicos. [ABSTRACT FROM AUTHOR]

Artificial incubation is needed to multiply the chicken yield especially in the upcoming economies where the provision falls short of its demand. Heat is the major factor among the indispensable requirements of successful egg incubation. Hence, the main focus of this work is to identify the sources of energy used in poultry egg incubations and to determine the hatchability rate of the poultry egg incubators based on energy source used. The method of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was used. Series of eligibility/exclusion criteria were applied: only journal articles, peer reviewed conference papers and government publications were selected; articles in English publications were chosen as well. Only papers published from April, 2022 downwards were covered. The study found that sources of energy for egg incubation are categorized into grid supply electricity, solar system, fossil fuel, biogas and thermochemical materials. From the reviewed articles, 50% identified grid-supplied electricity as energy source for poultry egg incubation and hatchability ranges from 80.9% - 98.39%. However, due to erratic nature of electricity supply and non-availability in rural areas especially in developing nations, the study recommends increased research interest on other energy sources to improve their hatchability. [ABSTRACT FROM AUTHOR]

SUMMARY: Recommendations for the optimal stocking density (SD) of chicks within transport boxes have not previously been published, with current recommendations lacking scientific support. As a result of concerns from welfare organizations regarding high SD in delivery boxes, a field trial was conducted at a commercial hatchery to understand SD effects on chick stress and box microclimate. Lohmann LSL-Lite chicks (n = 3,630) were placed in plastic transport boxes (58 × 46 cm) for a 7-h simulated transport period (uncontrolled humidity; 27°C). The SD treatments (trt) used were 80, 100, or 120 chicks/box (33.4, 26.7, or 22.2 cm2/chick). Group body weight (BW); vent temperature; concentrations of corticosterone, electrolytes, and glucose; and yolk sac weights were measured pre- and post-trt. Temperature and relative humidity (RH) were recorded every 5 min in the boxes. Thermal images of the boxes were taken every h for box floor and chick surface temperature and to calculate spatial area used per chick. Body weight, vent temperature, yolk sac weights, and corticosterone concentration did not differ between SD trt post-trt. Box temperature and RH increased with increasing SD. Thermal images showed the minimum temperature was lowest, and temperature variability was greatest, in the 80 trt compared to the 100 and 120 trts. The spatial area used per chick differed between trt and chicks occupied less than the total spatial area available in all trt. In conclusion, within the conditions used in this study, altering SD did not affect bird wellbeing, but reducing the density increased temperature variability within the boxes.

Abstract A reliable and cost‐effective source of fingerlings is essential for the successful commercial aquaculture of black sea bass. This study aimed to determine the effects of nursery tank stocking densities on the growth performance, feed efficiency, survival, tolerance to shipping, and biochemical quality of juvenile black sea bass. In two experiments, different stocking densities were compared for black sea bass at different stages of development. In Experiment 1, intermediate stage juveniles (1.27 g mean wt) were stocked at densities of 4.5 and 6.5 fish per liter of tank volume. Growth performance and biochemical quality were similar between the two density treatments. In Experiment 2, early post‐metamorphic stage juveniles (mean wt. = 0.524 g) were compared using the same stocking densities. While the fish reared at 4.5 fish/L were slightly larger, there were no significant differences in growth performance or biochemical quality between the density treatments. After both experiments, the fingerlings from each density treatment showed high survival rates under acute crowding and simulated shipping conditions. The study demonstrates that high NT densities of 4.5 and 6.5 fish/L did not negatively impact the growth performance and quality of black sea bass fingerlings, providing transport‐ready fingerlings in a relatively short period.

Otoliths from 3473 chum salmon spawners caught at the mouth of Naiba River and at Bereznyakovsky and Sokolovsky salmon hatcheries in 2013–2019 are investigated. Almost all of the chum adults caught at the hatcheries were marked at one of them and obviously migrated toward the point where they were released being the fry. Moreover, the most of chum spawners caught at the mouth of Naiba River also had the mark of either Bereznyakovsky or Sokolovsky hatchery, which definitely contributed a significant portion of the total stock of chum salmon in Dolinsky district of Sakhalin region.

Objective: Aspergillosis is a disease that affects several species of birds and causes substantial losses in the poultry business. The purpose of the investigation was to identify the pathogen responsible for a respiratory outbreak among juvenile ducklings. Materials and Methods: An epidemic of Aspergillosis infected a total of 800 Muscovy ducks that were being reared in El-Beheira Governorate. Tissue samples were obtained to isolate suspected fungi from diseased birds and the hatchery environment. In addition, identification and molecular characterization were performed on the obtained fungal isolates. Results: Affected birds displayed acute respiratory manifestations such as difficulty breathing, gasping for air, nasal discharge, and a mortality rate of up to 28.1%. Postmortem examination revealed bronchitis, tracheitis, congested lungs, air sacculitis, severe multifocal granulomatous pneumonia, a congested, enlarged liver, and a congested kidney with nephritis. Mycological examination revealed seven Aspergillus (A.) spp. isolates from ducklings and six from hatcheries. Isolate colonial morphology and microscopical examination were as follows: A. fumigatus, A. niger, Syncephalastrum racemosum, and four untypable isolates. These isolates were further identified by polymerase chain reaction (PCR), and the internal transcribed spacers (ITSs) gene was detected. Four representative isolates were submitted for sequencing and further phylogenetic analysis. The source of duckling infection might be linked to the hatchery environment due to the observed similarity of isolates from both affected birds and the hatchery, as evidenced by phylogenetic analysis. Conclusion: Our findings demonstrated the significance of appropriate hatchery control in preventing infection in young ducklings. Furthermore, the use of molecular identification techniques would be helpful for tracing the source of infection and rapid diagnosis of Aspergillus in the field. [J Adv Vet Anim Res 2023; 10(4.000): 763-772]

ABSTRACTKelp aquaculture is typically a two-stage process, with an indoor nursery phase and a grow-out phase at sea. For the successful development and implementation of commercial kelp aquaculture, production of viable seeded lines in the nursery is essential. This study investigated optimal nursery conditions of three kelp species native to Tasmania, Australia: Ecklonia radiata, Lessonia corrugata, and Macrocystis pyrifera. The interactive effects of temperature (12°C, 15°C, and 18°C) and light level (~30 µmol photons s−1 m−2, and ~ 60 µmol photons s−1 m−2) on sporophyte length, sporophyte density, and contamination of spools were examined over a 34-day period. The optimal temperature and light levels were 15°C and 30 µmol photons m−2 s−1 for E. radiata, 12°C and 60 µmol photons m−2 s−1 for L. corrugata, and 12°C and 30 or 60 µmol photons m−2 s−1 for M. pyrifera. Under these optimal conditions, the mean ± SEM sporophyte lengths after 34 days were 0.60 ± 0.02 mm, 1.04 ± 0.04 mm, and 0.60 ± 0.01 mm for E. radiata, L. corrugata, and M. pyrifera, respectively. The mean ± SEM sporophyte densities for each of these three species were 15.5 ± 6.2 sporophytes cm−1 of line, 10.8 ± 5.9 sporophytes cm−1 of line, and 19.3 ± 8.1 sporophytes cm−1 of line, respectively. Contamination increased with increasing temperature and was not significantly affected by light level. This work highlights the need for a species- and ecotype-specific approach in the nursery phase to ensure successful seaweed aquaculture outcomes in new regions of cultivation.

A range of conservation and restoration tools are needed to safeguard the structure and function of aquatic ecosystems. Aquaculture, the culturing of aquatic organisms, often contributes to the numerous stressors that aquatic ecosystems face, yet some aquaculture activities can also deliver ecological benefits. We reviewed the literature on aquaculture activities that may contribute to conservation and restoration outcomes, either by enhancing the persistence or recovery of one or more target species or by moving aquatic ecosystems toward a target state. We identified 12 ecologically beneficial outcomes achievable via aquaculture: species recovery, habitat restoration, habitat rehabilitation, habitat protection, bioremediation, assisted evolution, climate change mitigation, wild harvest replacement, coastal defense, removal of overabundant species, biological control, and ex situ conservation. This list may be expanded as new applications are discovered. Positive intentions do not guarantee positive ecological outcomes, so it is critical that potentially ecologically beneficial aquaculture activities be evaluated via clear and measurable indicators of success to reduce potential abuse by greenwashing. Unanimity on outcomes, indicators, and related terminology will bring the field of aquaculture–environment interactions into line with consensus standards in conservation and restoration ecology. Broad consensus will also aid the development of future certification schemes for ecologically beneficial aquaculture. [ABSTRACT FROM AUTHOR]

Fish hatcheries are widely used to enhance fisheries and supplement declining wild populations. However, substantial evidence suggests that hatchery fish are subject to differential selection pressures compared to their wild counterparts. Domestication selection, or adaptation to the hatchery environment, poses a risk to wild populations if traits specific to success in the hatchery environment have a genetic component and there is subsequent introgression between hatchery and wild fish. Few studies have investigated domestication selection in hatcheries on a genomic level, and even fewer have done so in parallel across multiple hatchery–wild population pairs. In this study, we used low‐coverage whole‐genome sequencing to investigate signals of domestication selection in three separate hatchery populations of Chinook salmon, Oncorhynchus tshawytscha, after approximately seven generations of divergence from their corresponding wild progenitor populations. We sequenced 192 individuals from populations across Southeast Alaska and estimated genotype likelihoods at over six million loci. We discovered a total of 14 outlier peaks displaying high genetic differentiation (FST) between hatchery–wild pairs, although no peaks were shared across the three comparisons. Peaks were small (53 kb on average) and often displayed elevated absolute genetic divergence (Dxy) and linkage disequilibrium, suggesting some level of domestication selection has occurred. Our study provides evidence that domestication selection can lead to genetic differences between hatchery and wild populations in only a few generations. Additionally, our data suggest that population‐specific adaptation to hatchery environments likely occurs through different genetic pathways, even for populations with similar standing genetic variation. These results highlight the need to collect paired genotype–phenotype data to understand how domestication may be affecting fitness and to identify potential management practices that may mitigate genetic risks despite multiple pathways of domestication. [ABSTRACT FROM AUTHOR]

A reliable and cost‐effective source of fingerlings is essential for the successful commercial aquaculture of black sea bass. This study aimed to determine the effects of nursery tank stocking densities on the growth performance, feed efficiency, survival, tolerance to shipping, and biochemical quality of juvenile black sea bass. In two experiments, different stocking densities were compared for black sea bass at different stages of development. In Experiment 1, intermediate stage juveniles (1.27 g mean wt) were stocked at densities of 4.5 and 6.5 fish per liter of tank volume. Growth performance and biochemical quality were similar between the two density treatments. In Experiment 2, early post‐metamorphic stage juveniles (mean wt. = 0.524 g) were compared using the same stocking densities. While the fish reared at 4.5 fish/L were slightly larger, there were no significant differences in growth performance or biochemical quality between the density treatments. After both experiments, the fingerlings from each density treatment showed high survival rates under acute crowding and simulated shipping conditions. The study demonstrates that high NT densities of 4.5 and 6.5 fish/L did not negatively impact the growth performance and quality of black sea bass fingerlings, providing transport‐ready fingerlings in a relatively short period. [ABSTRACT FROM AUTHOR]

Simple Summary: The development of cost-effective protocols with optimized rearing systems and conditions is an essential requirement to assure the economic feasibility of mussel production in hatchery systems. The Mediterranean mussel Mytilus galloprovincialis plays a relevant role on the scale of bivalve aquaculture, whose expansion has deep economic and environmental consequences. The current study establishes the protocols to improve pediveliger settlement, post-larvae production and growth, through the optimization of the stocking density of larvae and post-larvae in hatchery systems. This standardized protocol for mussel rearing can enhance the production of quality seed to supply the fattening industry as well as for environmental restoration. In mussel hatchery systems, the settlement process is a crucial element influencing seed yield. The current study assayed the influence of five densities of competent pediveliger larvae on settlement success and post-larvae production. We showed an inverse relationship between density and settlement efficiency, e.g., an attachment success of 99.4% at the lowest density (35 larvae/cm2) but only 9% at the highest density (210 larvae/cm2). However, post-larvae production was higher at intermediate larvae densities (70 larvae/cm2). The reimplementation of treatments upon post-larvae density after 6 weeks post settlement showed that the lowest-density groups bore both the highest post-larvae growth rate (22.24 ± 4.60 µm/day) and the largest head batch (48% of the size distribution), as compared to the higher-post-larvae-density groups. These results highlight the importance of optimizing both pediveliger larvae density and post-larvae density, to maximize high-quality seed yield in local hatcheries. Current rearing technologies would assure a timely commercial seed production to protect natural sea rocky beds in Alboran Sea coasts. [ABSTRACT FROM AUTHOR]

Obtaining viable Argopecten purpuratus seeds faces challenges, especiallyci the unpredictability of the marine environment and high production costs in hatcheries. However, improving the method of "Broodstock Conditioning In Hatcheries" is key to ensure permanent seed supplies by minimizing the dependence on marine conditions and by maximizing economic viability in hatcheries. In an effort to overcome these barriers, broodstock were conditioned into two different environments: (a) Natural Environment: Natural marine conditions located in Bahía Inglesa, Atacama Region, Chile. (b) Hatchery: Laboratory conditions to achieve gonadal maturation, spawning induction, fertilization and larval development. The purpose of this research was to evaluate how the type of reproductive conditioning affects the reproductive potential and nutritional quality of the progeny. Both methods were successful at inducing the necessary maturity for reproduction, obtaining viable gametes and larvae. On the other hand, it was observed that in the natural environment, the oocytes and D larvae reached a greater size and nutritional value, being the most significant differences with (p < 0.05): the size of the D larvae reached figures of 95.8 ± 3.1 μ m and 91.2 ± 2.7 μ m in the environment and hatchery, respectively; the lipid content in dry mass was 25.2 ± 3.1 mg g − 1 and 13.5 ± 1.9 mg g − 1 for the natural environment and hatchery, respectively. Although quality indicators in hatcheries were slightly lower compared to the natural environment, the possibility of conditioning A. purpuratus broodstock independently of environmental variability highlights the importance of further optimizing broodstock conditioning aspects in hatcheries that would allow more predictable and sustainable production. [ABSTRACT FROM AUTHOR]

Hatcheries have the power to spread antimicrobial resistant (AMR) pathogens through the poultry production chain. Enterococci are commensal intestinal bacteria and opportunistic pathogens in humans and animals. The aim of this study was to assess the occurrence of enterococci in broiler breeder hatcheries in 3 different governorates in Egypt “Sharqia, Beheira, and Dakahlia” with regard to the manifested diseases. The isolation results revealed that E. faecalis occurrence in the examined samples were 5.4% (65/1200) from pipped chicks’ yolk sacs and 5.8% (69/1200) from live chicks’ organs. The antibiotic susceptibility testing of the recovered isolates showed high resistance to vancomycin, oxytetracycline and high sensitivity for penicillin, difloxacin and amikacin. The genetic screening for some virulence and antibiotic resistance genes indicated the high incidence of gelE and asa1 virulence genes between the recovered isolates in correlation with the high incidence of ermB and blaZ antibiotic resistance genes. In conclusion, hygienic measures in breeders' hatcheries are recommended to avoid the spreading of resistance and virulent E. faecalis as it represents a public health threat in addition to its deleterious effects on poultry production. [ABSTRACT FROM AUTHOR]

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This study aimed to evaluate the effect of in ovo injection of folic acid (FA) and sulfur amino acids (SAAs) on the mitotic activity of myocytes, performance, relative organ weight, hematological values, and characteristics of broiler chicken carcasses. A total of 1200 fertile eggs from 42-week-old Ross AP© breeders were inoculated in the albumen on the first day of incubation in a completely randomized design with one of the treatments: C—intact eggs; SS: inoculation with 0.5 mL of saline solution; FA: 0.150 mg of FA; SAA: 5.90 mg of L-methionine and 3.40 mg of L-cysteine; or FA/SAA: FA + SAA. The inoculation of SAA did not influence (p > 0.05) the post-hatching characteristics of the chickens. FA inoculation increased (p < 0.05) the expression of the PAX7 and MYF genes in the pectoralis muscle of hatched chicks and reduced (p < 0.05) feed conversion at 42 days of age. The combination of SAA + FA increased (p < 0.05) the depth of the ileal crypt on the 1st day after hatching and the relative weight of the spleen and thymus on the 21st day of life. In conclusion, the inoculation of FA on the 1st day of incubation increases gene expression and improves the performance of broilers. [ABSTRACT FROM AUTHOR]

Variation in sand composition at the individual beach level is an important factor for hatching success and hatchling phenotype that does not appear to have been previously investigated. We studied variation in intrabeach substrate composition in an important loggerhead turtle (Caretta caretta) nesting colony on the island of Maio, Cabo Verde, and examined its relationship with embryonic development success, hatchling phenotype, and hatchling vitality. Thirty-two nests from different females were studied under experimental conditions, controlling for beach position, depth, humidity, and temperature in a randomized block design. Two sand treatments corresponding to 2 types of sand from the same beach were used. While nesting females selected nesting sites indiscriminately between substrate types, their nests differed significantly in all variables measured for reproductive success (hatching success, hatchling size, and hatchling agility) between the 2 sand types. Therefore, the intrabeach observations of substrate phenotype of progeny found here could differentially affect offspring survival. The effects of choosing different nesting sites will generally act to spread the probability of selective pressures on embryos. Variation in reproductive success was due to differences between substrate types within the beach rather than the location of nests within the beach. The importance of determining sand types with the highest hatching success, even within the same beach, should be greatest in colonies or populations highly threatened with extinction, where the hatching success of each nest becomes of utmost importance. [ABSTRACT FROM AUTHOR]

Although it is widely accepted that stocking hatchery‐cultured fish can increase the number of fish, decades of scientific evidence have shown that most often those stocking efforts fail to provide the desired "demographic boost" to a naturally reproducing, self‐sustaining target population. Despite this evidence, fish stocking remains a mainstay of fisheries management programmes, even as the biodiversity of wild fish populations and other aquatic organisms are at serious risk due to habitat loss and/or overexploitation across the globe. In this perspective piece, we summarise the reasons why wild and hatchery‐produced fish are not equivalent and describe the genetic and ecological risks associated with stocking programmes. We then present our perspective on the institutional changes that need to occur to assess these risks and offer ways to transition fisheries management strategies to become more effective in conserving levels of aquatic biodiversity from populations to landscapes. We propose that a critical first step to control ill‐conceived fish stocking programmes is to have each country develop, implement, and enforce a scientifically sound National Fish Stocking Policy. To achieve the long‐term sustainability of native fish populations, it is imperative that ecological and evolutionary principles be better integrated into future conservation strategies and management actions. [ABSTRACT FROM AUTHOR]

Objective: A goal of many segregated salmonid hatchery programs is to minimize potential interbreeding between hatchery‐ and natural‐origin fish. Our objective was to assess this on the Klickitat River, Washington, USA. Methods: We used radiotelemetry to evaluate spatiotemporal spawning overlap between hatchery‐ and natural‐origin steelhead Oncorhynchus mykiss and spring Chinook Salmon O. tshawytscha. We estimated percentages of tagged fish that spawned naturally in the Klickitat River subbasin, emigrated from the Klickitat River, or died before spawning. A kernel density analysis was used to estimate probability of spatiotemporal overlap between hatchery‐ and natural‐origin spawners. Result: For steelhead, 12% of hatchery‐origin and 50% of natural‐origin fish spawned naturally. For spring Chinook Salmon, 18% of hatchery‐origin and 44% of natural‐origin fish spawned naturally. Tag loss may result in underestimates in these percentages. Most hatchery‐origin steelhead (90%) spawned downstream of river kilometer (rkm) 32, and 75% spawned from November to mid‐March. The majority of natural‐origin steelhead (64%) spawned upstream of rkm 32, and 75% spawned from mid‐March to late May. Spawn timing of hatchery‐origin Chinook Salmon (early August to mid‐September) overlapped with that of natural‐origin Chinook Salmon (late July to late September), and fish of both origins spawned in the same 30‐km reach of the river. We estimated the percentage of hatchery‐origin spawners (pHOS) on the natural spawning grounds to be 12% for steelhead and 40% for spring Chinook Salmon across all study years. For steelhead, we estimated the overlap probability to be 25% (95% CI = 22.5–28%). For spring Chinook Salmon, tight spatial clustering of hatchery‐origin fish resulted in a lower overlap estimate of 21% (13–31%). Conclusion: We suggest adjusting pHOS estimates using these overlap estimates or similar spatiotemporal data on actual spawner proximity and possible interactions, and that these types of analyses be used in conjunction with gene flow analysis to accurately evaluate effects of individual hatchery programs. Impact statementPacific Salmon and steelhead hatchery programs provide important fishery and conservation benefits. We monitored interactions between hatchery and wild populations by tracking radio‐tagged fish and their degree of actual physical overlap in space and time to better inform management and recovery of this critical resource. [ABSTRACT FROM AUTHOR]

Objective: Aspergillosis is a disease that affects several species of birds and causes substantial losses in the poultry business. The purpose of the investigation was to identify the pathogen responsible for a respiratory outbreak among juvenile ducklings. Material and Methods: An epidemic of Aspergillosis infected a total of 800 Muscovy ducks that were being reared in El-Beheira Governorate. Tissue samples were obtained to isolate suspected fungi from diseased birds and the hatchery environment. In addition, identification and molecular characterization were performed on the obtained fungal isolates. Results: Affected birds displayed acute respiratory manifestations such as difficulty breathing, gasping for air, nasal discharge, and a mortality rate of up to 28.1%. Postmortem examination revealed bronchitis, tracheitis, congested lungs, air sacculitis, severe multifocal granulomatous pneumonia, a congested, enlarged liver, and a congested kidney with nephritis. Mycological examination revealed seven Aspergillus (A.) spp. isolates from ducklings and six from hatcheries. Isolate colonial morphology and microscopical examination were as follows: A. fumigatus, A. niger, Syncephalastrum racemosum, and four untypable isolates. These isolates were further identified by polymerase chain reaction (PCR), and the internal transcribed spacers (ITSs) gene was detected. Four representative isolates were submitted for sequencing and further phylogenetic analysis. The source of duckling infection might be linked to the hatchery environment due to the observed similarity of isolates from both affected birds and the hatchery, as evidenced by phylogenetic analysis. Conclusion: Our findings demonstrated the significance of appropriate hatchery control in preventing infection in young ducklings. Furthermore, the use of molecular identification techniques would be helpful for tracing the source of infection and rapid diagnosis of Aspergillus in the field. [ABSTRACT FROM AUTHOR]

ABSTRACT: Hatchery performance is often evaluated based on descriptors such as hatchability, 7-d mortality, and cost. In addition to these descriptors, it is useful to include in this analysis aspects of chick quality through post-hatch performance. Realizing the bird's complete genetic potential necessitates meeting various criteria, with effective support for the chick's immune system being among the pivotal factors. To be effective, in ovo vaccination systems must deliver the vaccines to specific sites in the egg, a circumstance that directly depends on when the injection is made. We examined production data to evaluate the impact of in ovo vaccination time on performance parameters of male Ross308AP chicks. A comprehensive survey was conducted examining records from 3,722 broiler flocks produced and raised by the same company under standard nutrition and management conditions. The selected data specifically pertained to flocks that underwent slaughter between 41 and 45 d. In our analysis, 4 different linear models were built, one for each response variable: mean weight (MW), body weight gain (BWG), corrected feeding conversion rate (cFCR), and total mortality (TM). The linear models used in the analyses included as main predictor the timing of in ovo vaccination (440, 444, 448, 452, 456, 458, and 460 h of incubation), and as additional predictors: age of the breeding flock (26–35, 36–55 and 56–66 wks old), slaughter age, identity of the hatchery, and the season at which the data was collected. Our results showed that the timing of in ovo vaccination significantly affected BWG and cFCR, with procedures performed at 460 h of incubation showing the best outcomes. Breeding flock age affected all response variables, with older breeding flocks delivering increased MW, BWG and TM, and middle-aged flocks increased cFCR. Increasing slaughter age reduced BWG while MW, cFCR and TM were all increased. These data emphasize the benefits of performing in ovo vaccination as close as possible to 460 h of incubation to extract the best BWG and cFCR from Ross308AP male broiler.

Abstract The marine migration of Atlantic salmon (Salmo salar) has been prioritised for research internationally as populations of S. salar have declined significantly throughout the species’ range. The main objectives of this study were to use acoustic telemetry to partition survival during the early migration phase, investigate potential causes of mortality and establish diurnal and tidal influences on movements. In 2017 and 2018 wild (n = 49) and hatchery (n = 81) S. salar smolts were tagged with acoustic transmitters. Migration was monitored through a brackish tidal lake, which discharges through a short estuary into northeast Clew Bay in Ireland situated in the northeast Atlantic. Partitioned survival through each area was similar for both wild and hatchery smolts and both groups followed the same migration routes, travelling along the main current out of Clew Bay. Total survival was high within the brackish lake (wild = 98% ± 1.21 and hatchery = 100%) and estuary (wild = 98% ± 1.01 and hatchery = 89% ± 9.28) compared to the marine environment (wild = 67% ± 4.39 and hatchery = 66% ± 7.91). Leaving the brackish lake during an ebb tide and entering the marine environment during daylight increased the probability of survival through the early marine period. The majority of smolts transited through the study area during ebb tides. Migration of hatchery smolts occurred mainly during hours of daylight while wild smolt migration showed no diel patterns. High mortality rates during the initial stages of the marine migration have consequences for the persistence of salmon populations and should be addressed through regionally tailored management measures and conservation efforts aimed at increasing the resilience of salmon stocks.

One of the main threats to aquaculture is represented by microbial pathogens, causing mass mortality episodes in hatcheries, which result in huge economic losses. Among the many disinfection methods applied to reduce this issue, the use of chemicals and beneficial microorganisms (probiotics) seems to be the most efficient. The aim of this study is to test the efficacy of two of them: a chemical, peracetic acid (PAA), and a probiotic, Phaeobacter inhibens. Tests were run on microalgae of the species Isochrysis galbana (var T-ISO). For both remedies, the microalgae survival rate and final cell concentration (cell/mL) were monitored. PAA analysis tested six different concentrations of the chemical: 7.5 µg, 10 µg/L, 20 µg/L, 30 µg/L, 40 µg/L, and 60 µg/L. Meanwhile, P. inhibens was tested with a concentration of 104 CFU/mL. Analysis for both the remedies was conducted on a laboratory scale using glass flasks, and on an industrial scale inside photobioreactors (PBRs). Among all the treatments, the one with PAA dosed with a concentration of 60 µg/L gave the best results, as the culture reached a final density of 8.61 × 106 cell/mL. However, none of the remedies involved in the experiment harmed microalgae or their growth. The results match perfectly with the condition requested for the tested remedies: to obtain an optimal breakdown of pathogens without interfering with culture growth. These features make PAA and P. inhibens good candidates for disinfection methods in aquaculture facilities.

Lumpfish are broadly used as biological sea lice removers in Norwegian salmon farming and are mostly produced in hatcheries. To date, there is little systematic documentation on the mortality causes of lumpfish in hatcheries. In the current study, data from 12 selected fish groups from four hatcheries in Norway were collected to understand the challenges and opportunities related to the categorization of mortality causes of lumpfish in hatcheries. This study indicated that a high proportion of lumpfish mortality was categorized by the hatcheries as unspecified. When specified, mortality was primarily assessed as due to fin damage. Our analyses showed that mortality categorized as fin damage correlated with the detection of infectious agents in dead fish, suggesting that mortality was due to infections rather than fin damage. It was not possible to conclude whether infection with pathogens present in the environment caused fin damage or if injuries from aggression were a gateway for pathogens. Furthermore, due to the lack of information regarding production conditions, it was not possible to assess risk factors causing eventual aggression or the presence of pathogens. This study revealed that mortality causality—the chain of events leading to death—is mainly unclear in lumpfish hatcheries because (1) mortality categorization does not focus on underlying causes and (2) there is little documentation of production conditions, making it very difficult to relate mortality rates to external factors. The present findings highlight that there are gaps in the registrations made by hatcheries and that there is an urgent need to implement standardized monitoring protocols for lumpfish hatcheries. This will help identify the causes of mortality and, therefore, allow for the implementation of proper measures that will ensure better survival.

The influence of temperature on development, growth and survival of pacific oyster Crassostrea gigas embryos and larvae is investigated in controlled conditions at a hatchery located in Peter the Great Bay (Japan Sea) — the TINRO subdivision for mariculture on Popov Island in July-August, 2019. The oyster embryos and larvae obtained from natural producers in the process of artificial spawning were grown under temperature of 21–22 оC (close to natural conditions in the coastal waters of Primorye) and 24–25 оC. The higher temperature had a positive effect on development and growth rate of embryos and larvae. Under the temperature of 24–25 оC, the embryogenesis was completed earlier by 2 hours, the transition to the D-veliger stage — by 8 hours, the stage of veliconch was reached in 1 day earlier, the stage of pediveliger — in 4 days earlier than under the temperature of 21–22 оC. The daily size increments were larger under the higher temperature, with the most significant differences at the stages of veliger (6.4 vs 4.2 µm day–1) and veliconch (14.3 vs 10.9 µm day–1), with no difference at the stage of pediveliger. The greatest average daily increment was reached with exotrophic nutrition (at the veliconch stage) in both cases. The larval mortality was higher under the higher temperature in 1.3 times at the stages from fertilized egg to D-veliger and in 1.4 times at the stages from D-veliger to pediveliger because of intensification of metabolic processes and the water pollution in the tanks for growing, with the largest difference at the stages of veliger and veliconch, as well, as the longest ones. There is concluded that the temperature of 24–25 оC lays within the range of optimal conditions for embryonic and larval development of pacific oyster (within the biokinetic zone) and this temperature is recommended for cultivation of this species in Primorye hatcheries, with selection of optimal parameters for the rearing.

Abstract Larval eastern oysters (Crassostrea virginica) grown in shellfish hatcheries are susceptible to bacterial diseases, particularly vibriosis. Probiotics are microbes that confer health benefits to the host and have been identified as promising tools to manage diseases in aquaculture. The marine bacterium Phaeobacter inhibens S4 (S4) protects larval eastern oysters against challenge with the bacterial pathogen Vibrio coralliilyticus RE22 (RE22). A concentrated liquid formulation of probiont S4 that maintained high cell viability after long‐term storage was developed for commercial use in shellfish hatcheries. The safety and efficacy of the formulation were tested in six different trials in two hatcheries. The S4 formulation was added to C. virginica larvae culture tanks daily at 104 colony forming units (CFU)/mL from Day 1 post fertilisation until Day 6, 12 or 14, depending on the trial. Treatment of larvae in the hatchery with the S4 formulation did not significantly affect the survival and growth of the larvae. Formulated probiont S4 treatment in the hatchery led to a significant increase in relative percent survival (RPS) when larvae were subsequently challenged with the pathogen RE22 (105 CFU/mL) for 24 h in a laboratory challenge as compared to probiotic‐untreated RE22‐challenged larvae (RPS increase of 46%–74%, p

Abstract Fish hatcheries are widely used to enhance fisheries and supplement declining wild populations. However, substantial evidence suggests that hatchery fish are subject to differential selection pressures compared to their wild counterparts. Domestication selection, or adaptation to the hatchery environment, poses a risk to wild populations if traits specific to success in the hatchery environment have a genetic component and there is subsequent introgression between hatchery and wild fish. Few studies have investigated domestication selection in hatcheries on a genomic level, and even fewer have done so in parallel across multiple hatchery–wild population pairs. In this study, we used low‐coverage whole‐genome sequencing to investigate signals of domestication selection in three separate hatchery populations of Chinook salmon, Oncorhynchus tshawytscha, after approximately seven generations of divergence from their corresponding wild progenitor populations. We sequenced 192 individuals from populations across Southeast Alaska and estimated genotype likelihoods at over six million loci. We discovered a total of 14 outlier peaks displaying high genetic differentiation (FST) between hatchery–wild pairs, although no peaks were shared across the three comparisons. Peaks were small (53 kb on average) and often displayed elevated absolute genetic divergence (Dxy) and linkage disequilibrium, suggesting some level of domestication selection has occurred. Our study provides evidence that domestication selection can lead to genetic differences between hatchery and wild populations in only a few generations. Additionally, our data suggest that population‐specific adaptation to hatchery environments likely occurs through different genetic pathways, even for populations with similar standing genetic variation. These results highlight the need to collect paired genotype–phenotype data to understand how domestication may be affecting fitness and to identify potential management practices that may mitigate genetic risks despite multiple pathways of domestication.