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Simple Summary: Native chickens generally have the characteristics of low growth performance, which has also become a limiting factor for the breeding of yellow feather broilers. More and more studies have shown that gut microbiota plays an important role in the growth of livestock farming. The Guizhou yellow chicken is a breed of yellow-feathered broiler chicken with excellent meat quality and good flavor currently being cultivated in Guizhou Province, China. In order to explore the role of gut microbiota on the growth performance of native chickens, the Guizhou yellow chicken was taken as a representative, and high-market-weight and low-market-weight chicken groups were established according to their market weights. By integrating microbial 16S rRNA gene sequencing and non-targeted serum metabolome data, five key cecal microbes associated with high body weight in chickens and one key microbe associated with low body weight were identified. In addition, the results also showed that specific gut microbes might positively affect the growth rate of chickens by regulating vitamin and other metabolic pathways. These findings might improve understanding of the role of gut microbiota in chicken growth traits and their underlying metabolic mechanisms. The gut microbiota plays an important role in the physiological activities of the host and affects the formation of important economic traits in livestock farming. The effects of cecal microbiota on chicken weights were investigated using the Guizhou yellow chicken as a model. Experimental cohorts from chickens with high- (HC, n = 16) and low-market-weights (LC, n = 16) were collected. Microbial 16S rRNA gene sequencing and non-targeted serum metabolome data were integrated to explore the effect and metabolic mechanism of cecal microbiota on market weight. The genera Lachnoclostridium, Alistipes, Negativibacillus, Sellimonas, and Ruminococcus torques were enriched in the HC group, while Phascolarctobacterium was enriched in the LC group (p < 0.05). Metabolomic analysis determined that pantothenic acid (vitamin B5), luvangetin (2H-1-benzopyran-6-acrylic acid), and menadione (vitamin K3) were significantly higher in HC serum, while beclomethasone dipropionate (a glucocorticoid) and chlorophene (2-benzyl-4-chlorophenol) were present at higher levels in the LC group. The microbes enriched in HC were significantly positively correlated with metabolites, including pantothenic acid and menadione, and negatively correlated with beclomethasone dipropionate and chlorophene. These results indicated that specific cecal bacteria in Guizhou yellow chickens alter the host metabolism and growth performance. This study provides a reference for revealing the mechanism of cecal microbe actions that affect chicken body weight. [ABSTRACT FROM AUTHOR]

The purpose of the current study was to examine transcriptomic-based profiling of differentially expressed innate immune genes between indigenous and commercial chickens. In order to compare the transcriptome profiles of the different chicken breeds, we extracted RNA from blood samples of the Isfahan indigenous chicken (as indigenous) and Ross broiler chicken (as commercial) breeds. RNA-Seq yielded totals of 36,763,939 and 31,545,002 reads for the indigenous and commercial breeds, respectively, with clean reads then aligned to the chicken reference genome (Galgal5). Overall, 1327 genes were significantly differentially expressed, of which 1013 genes were upregulated in the commercial versus the indigenous breed, while 314 were more highly expressed in the indigenous birds. Furthermore, our results demonstrated that the SPARC, ATP6V0D2, IL4I1, SMPDL3A, ADAM7, TMCC3, ULK2, MYO6, THG1L and IRG1 genes were the most significantly expressed genes in the commercial birds and the PAPPA, DUSP1, PSMD12, LHX8, IL8, TRPM2, GDAP1L1, FAM161A, ABCC2 and ASAH2 genes were the most significant in the indigenous chickens. Of notable finding in this study was that the high-level gene expressions of heat-shock proteins (HSPs) in the indigenous breeds could serve as a guideline for future genetic improvement. This study identified genes with breed-specific expression, and comparative transcriptome analysis helped understanding of the differences in underlying genetic mechanisms between commercial and local breeds. Therefore, the current results can be used to identify candidate genes for further breed improvement. [ABSTRACT FROM AUTHOR]

Simple Summary: Soft scalding at 57 °C for 120 s is suitable for broiler chickens for desirable defeathering effects and favorable breast meat and skin color. Hard scalding at 60 °C for 60 s is optimal for layers and the local strain of RF country chickens because of its capacity to ease defeathering and retain acceptable carcass skin color and elasticity. Current soft scalding in broilers is not applicable to various strains of chickens with different market weights and ages. This study aimed to examine the effectiveness of soft (57 °C for 120 s) and hard (60 °C for 60 s) scalding on defeathering and carcass quality of the local strain of Red Feather (RF) country chickens and determine age, breed, and body weight factor in accounting for the defeathering effectiveness using adult layers and juvenile broilers as a reference. Results showed no differences between soft and hard scalding in broilers with 60% and 80% of acceptable defeathering scores, respectively, while a significantly better effect by hard scalding was observed in adult layers, young and old RF chickens with more than 70% of birds exhibiting desirable scores and less than 20% by soft scalding. In contrast to soft scalding, hard scalding had no significant effects on breast meat color but impaired skin color in broilers as assessed by L*, a*, and b* value analysis. Interestingly, hard scalding increased breast skin yellowness and lightness in young RF chickens and lightness in old RF chickens, while there were no significant changes in layers. However, hard scalding decreased skin elasticity in layers and old RF chickens. The effectiveness of defeathering by scalding method was governed by the age to reach a certain threshold in the development of dermal architecture and feather richness, irrelevant to body weight. The alteration of carcass color primarily depends on age, body weight/breed, and their interaction. In conclusion, current soft scalding is suitable for broiler chickens for desirable defeathering effect and carcass color, whereas layers and RF chickens scaled at 60 °C for 60 s showed a better defeathering effect without unfavorable changes of breast meat and skin color. [ABSTRACT FROM AUTHOR]

Simple Summary: Crude fiber levels that are not controlled in chicken diets could have adverse effects on productivity. The use of alternative protein resources in commercial broiler and indigenous chicken production often has limitations in terms of dietary crude fiber. Evidence suggests that there might be differences in the way chicken breeds cope with dietary crude fiber, which ultimately affects the production potentials. The study determined the levels of dietary crude fiber that enhanced the productivity in Ross 308 broiler and indigenous Venda chickens. Results showed that both chicken breeds aged 1 to 42 days required dietary crude fiber for enhanced productivity. However, indigenous Venda chickens required higher dietary CF levels in order to improve the production performance than the Ross 308 broiler chickens. Thus, it was concluded that the indigenous chickens were able to cope when challenged with higher dietary crude fiber levels. The study determined the effects of dietary crude fiber (CF) levels on the production performance of male Ross 308 broiler and indigenous Venda chickens. There were 360 male Ross 308 broiler and male Venda chickens aged 1–21 for Phase 1 and 196 chickens aged 22–42 days for Phase 2. Chickens were allocated four diets with different levels of CF (3, 4, 5, and 7%) in a completely randomized design. Quadratic regression analyses were used to determine the dietary CF levels for the optimal production responses. In Phase 1, the feed intake, growth, live weight, nitrogen retention, and metabilizable energy (ME) intake of the Ross 308 broiler chickens were improved at dietary CF levels of 3.9, 4.5, 4.5, 3.2, and 3.7%, respectively. In the Venda chickens, feed intake, growth, live weight, nitrogen retention, and ME intake were optimized at 4.4, 4.8, 4.7, 4.1, and 3.3% CF, respectively. In Phase 2, the feed intake, nitrogen retention, and neutral detergent fiber digestibility (NDFD) were enhanced at CF levels of 6.4, 4.4, and 3.7% in the Ross 308 broiler chickens, respectively. Dietary CF levels of 4.5, 5.8, 5.7, 5.1, 3.9, and 4.4% optimized the feed intake, growth rate, live weight, nitrogen retention, NDF, and ADFD, respectively, in Venda chickens. It was concluded that the indigenous Venda chickens coped better with higher dietary CF than the Ross 308 broiler chickens. [ABSTRACT FROM AUTHOR]

In the broiler-breeding industry, phenotype determination is critical. Leg weight is a fundamental indicator for breeding, and noninvasive testing technology can reduce damage to animals. This study proposes a broiler leg weight estimation system comprising a weight-estimation model and computed tomography (CT) acquisition equipment. The weight-estimation model can automatically process the scan results of live broiler chickens from the CT acquisition equipment. The weight-estimation model comprises an improved you-only-look-once (YOLOv5) segmentation algorithm and a random forest fitting network. The segmentation head was introduced into the YOLOv5 network, combined with a multiscale attention mechanism and an atrous spatial pyramid pooling architecture, and a new network model, YOLO- measuring chicken leg weight (YOLO-MCLW), was proposed to improve segmentation efficiency and accuracy. Morphological parameters were extracted from the obtained mask image, and a random forest network was used for fitting. The experiments show that the system exhibited an average absolute error of 7.27 g and an average percentage error of 4.82% in tests on 50 individual legs of 25 broiler chickens. The prediction R 2 of broiler chicken legs can reaches 88.98%, the segmentation intersection over union result reaches 95.45%, and 37.04 images are processed per second. This system provides technical support for the part determination of broiler chickens in commercial breeding. [ABSTRACT FROM AUTHOR]

This study investigated the immune responses to La Sota vaccination, used in protection of chickens against Newcastle disease, in light weight type breeds of chickens (pullets) and heavy weight type breeds of chickens (broilers) used in commercial poultry production. Seven‐week‐old 50 White Marshall broilers (Br) and 50 Isa Brown pullets (Pu) were randomly divided into four groups: vaccinated broilers chickens; (VBr), unvaccinated broiler chickens (UBr), and vaccinated pullet chickens (VPu) and unvaccinated pullet chickens (UPu). Chickens in groups VBr and VPu were vaccinated with La Sota vaccine, whereas groups UBr and UPu were not vaccinated. On day 0 post vaccination (PV), six chickens from group Br and Pu, and on day 4 PV, three chickens from each four groups were sacrificed and the bursa weight index (BWI), thymus weight index (TWI) and the splenic weight index (SWI) were obtained. The chickens were observed for clinical signs and lesions. Serum samples were collected from the chickens in all the groups on days 0, 7, 14, 21, 28 PV and assayed for haemagglutination inhibition (HI) antibodies. The BWI, TWI and SWI were 0.37 ± 0.05, 0.35 ± 0.17, 0.65 ± 0.26 for pullets and 0.11 ± 0.04, 0.13 ± 0.02, 0.36 ± 0.17 for broilers on day 0 PV. On day 4 PV there was no significant difference (p <.05) between the indices of the vaccinated and unvaccinated chickens. The geometrical mean antibody titres (GMT) of the pullets were 2 to 3 times higher than those of the broilers on days 7 to 28 PV. Vaccination did not produce clinical signs or lesions. The above observations show that naturally pullets produce higher antibodies than broilers because of their higher BWI. [ABSTRACT FROM AUTHOR]

The FUNAAB Alpha broiler, a tropical chicken breed developed in Nigeria, has three genotypes which are normal feather (NF), naked neck (NN), and frizzle feather (FF). This 56-day study investigated the effect of genotype on growth, fear-related behaviours, and walking ability of FUNAAB Alpha broiler chickens. Two hundred and four (204) chickens (68 NF, 68 NN, and 68 FF chickens; 34 males and 34 females per genotype) were used for the experiment. Body weight and growth rate were measured on days 27 and 56. The level of fear using the tonic immobility test (TI) on days 23 and 51, and emergence from a dark box on days 25 and 53 were measured. Walking ability was assessed using the latency to lie test on day 54. There was a genotype effect on body weight on days 27 and 56 (p = 0.02 and p = 0.01, respectively) and growth rate from days 1–27 and days 1–56 (p = 0.02 and p = 0.03, respectively). Of the three genotypes, the NN chickens were lighter in body weight, while the NF and FF had similar body weights on days 27 and 56 (p = 0.64 and p = 0.85, respectively), and growth rate from days 1–27 (p = 0.79). The male chickens were heavier on days 27 and 56 (p = 0.04 and p = 0.04, respectively) and had a better growth rate from days 1–27 (p = 0.03). The duration of tonic immobility on days 23 and 51 was similar in all three genotypes. The latency to emerge from a dark box on day 25 was not affected (p = 0.70) by genotype, but it took the NF chickens a longer time (138.20 ± 18.70 s) to emerge from the dark box on day 53. The walking ability of the birds was not affected (p = 0.83) by the genotype. However, male chickens had better (p = 0.01) walking ability by standing for a longer time than the females during the latency to lie test. In conclusion, the NF and FF chickens were heavier than the NN on days 27 and 56, and the NN and FF chickens were less fearful than the NF chickens on day 53. The FF genotype is recommended for meat production due to its better growth and less fearfulness. [Display omitted] • FUNAAB Alpha broiler chicken is a slow-growing breed developed in Nigeria. • Naked neck and frizzle feather chickens are less fearful than normal feather chickens. • Male FUNAAB Alpha broiler chickens had a better walking ability than female chickens. • Frizzle feather chickens had a better growth performance and were less fearful. [ABSTRACT FROM AUTHOR]

The reasearch aims to identify the business models of broiler production in South Konawe regency through the analysis of capital resource require and income of chicken breeders. The research applied census and Focus Group Discussion (FGD) to gather information. The research result shows that there are two models of broiler business, independent and partnership. Chicken breeders who carry out independent business deal with all production activities, including marketing their products. As well as using their own capital, they may take up loans. On the other hand, chicken breeders who enter into a partnership do so with companies that can provide capital and market. Chicken breeders undertake production activities while their partner companies provide capital and market. The number of individual chicken breeders was less compare to chicken breeders who perform partnership due to limited capital being available to them. The income of inividual chicken breeders however is higher than chicken breeders who carry out partnership. [ABSTRACT FROM AUTHOR]

In this experiment we have evaluated the productive performances of two broiler chicken genotypes, Ross 308 and Cobb 500 hybrids, raised in intensive system for a time-period of 42 days, in the same microclimate and feeding conditions. The body weight of chickens was established by weekly weighing, on entire research period, and the feed consumption and mortality were daily registered. The research results put into evidence a slightly superiority of body weight at delivery for Cobb 500 hybrid with 3.42% compared to Ross 308 hybrid. Also, the feed conversion index was in favor for Cobb 500 hybrid against Ross 308 hybrid, but the two registered values were very close. [ABSTRACT FROM AUTHOR]

To timely modify breeding scheme and improve selection efficiency of Dahen broiler, genetic and breeding progress analysis on five pure lines was conducted. The results showed that the selection on breeding goal traits of each line was effective since 14 generations, especially the selection on growth traits did not cause adverse influence on reproductive performance. After the 6t h generation, main performances of each line maintained in higher level, but the breeding progrees obviously declined. It iilustrated that current breeding means was effective for maintaining and consolidating breeding goal traits of Dahen broiler, and it should timely adjust breeding scheme to obtain more genetic progns. [ABSTRACT FROM AUTHOR]

The effects of different levels of dietary fat on calcium (Ca) and phosphorus (P) absorption growth performance, Ca and P percentages of plasma, bone and ash were studied in broiler chickens (Ross 308) during 56-days rearing period. A total of 360 one-day-old chicks randomly assigned to eight experimental groups, three replicates (10 birds per each) of both sex. The experimental groups with a 4 × 2 factorial design received either four levels of fat (0, 2, 4 & 6% of diet) or two levels of Ca (1 or 2% of diet). The results showed that administration of different fat levels to broiler diets were significantly improved growth performance (P< 0.01). Also Ca and P concentration of plasma, bone and ash were increased (P< 0.01) with the exception of bone ash (BA) (P> 0.01). The interaction between fat and Ca for bone P and plasma Ca and P was detected (P< 0.01). There were no interactions detected for feed intake, feed efficiency, carcass weight, ash P and bone Ca and P (P> 0.05). From these results, it was concluded that a combination of 2% animal fat and 1 or 2% Ca provides more suitable performance in broiler chickens and this combination could improve Ca and P absorption; however, higher levels of supplemented fat may decrease absorption rate. [ABSTRACT FROM AUTHOR]

1. Individually-caged Ross 308 broiler breeders were transferred temporarily at 147 d from 8 to 14-h photoperiods and back to 8 h at 5-d intervals from 5 to 25 d and at 32 d. Control birds were maintained on 8 h or transferred permanently to 14 h. 2. Five long days had minimal effect on age at first egg, between 10 and 25 long days progressively accelerated sexual development, and maximum advance was achieved by 32 long days. However, a model involving the ogive of a normal distribution with a mean of 14 long days and an SD of 5.3 indicated that 28 long days would be sufficient to maximise sexual development. 3. The similarity of this model for broiler breeders with one previously produced for egg-type pullets suggested a common physiological mechanism for photosexual responses to two opposing changes in photoperiod. [ABSTRACT FROM AUTHOR]