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Whey, obtained from cheese manufacturing, has a significant environmental impact due to its organic load and volume produced. Therefore, validating technologies that allow its valorization due to its content of ingredients of high nutritional or functional value becomes relevant for the dairy industry. Microparticulate whey protein (MWP) has been used to produce cheeses and has the potential to improve process performance. We seek to develop and optimize the characteristics of a MWP to be used to make white cheese. For this, factors such as temperature, from 73 to 93°C, and retention time from 3 to 17 min of the heat treatment were evaluated. We assessed zeta potential, particle size, color, protein retention coefficient, and cheese yield as response variables using a response surface design with 14 experiments. Optimum conditions were 93°C for 5.4 min retention. In the white cheese production, two inclusion percentages were tested: 3 and 5% (w/w); and the impact on characteristics like yield, protein retention, and texture was evaluated with respect to a control cheese that was not added with MWP. We found that 3% inclusion is more suitable because it keeps textural characteristics closer to traditional cheese. The MWPs add value to whey and cheese by improving performance and enabling the retention of proteins of high biological and nutritional value.

Whey is a liquid by-product obtained by cheese elaboration, which is not completely used due to the large quantities produced. As a result, the whey is poured into rivers and soils and becomes a pollutant agent. The valorization of acid whey using membrane clarification was evaluated, where the effect of temperature and membrane cut-off were studied using acid whey. Permeability was three times higher at 70°C than 50°C (163.2±11.1 y 62.4±9.2 L/m2 .h, respectively) for membranes with a cut-off of 0.2 µm. Furthermore, the permeate flux for this cut-off was three, six and ten times higher compared with the cut-off of 300, 150 y 50 kDa at 70°C, respectively. The clarification stage was scaled-up with 0.2 µm membranes, achieving about 22 L of whey filtered for Batch mode until a volume reduction factor (VRF) of 5 with protein retention of 68%. In Fed-Batch mode, the retention of protein was 61%, but the filtration could be carried out for longer, reducing fouling and filtering almost the double of the quantity of whey compared with Batch mode. In all cases, the turbidity of permeates was lower than 12 NTU (reduction >99%), regardless of whey turbidity whose values might be superior to 12,000 NTU. [ABSTRACT FROM AUTHOR]

Prawns (Macrobrachiumrosenbergii) is one of the freshwater shrimp species native to Indonesia. Shrimp prawns are the most popular of all freshwater shrimp because of its large size and has a high economic value in both domestic market and abroad. Problems commonly encountered in the cultivation of prawns currently includes several factors such as water quality, disease and feed. Efforts that can be done is by feeding in sufficient quantity and quality and not excessive is a very decisive factor. Technical constraints on the level of farmers are limited in supply mains quality. Therefore, efforts are needed to tackle these problems by managing the stock of prawns parents. This study aims to determine the addition of cod liver oil on a commercial feed can increase protein retention and energy retention prawns (Macrobrachium rosenbergii). This research was carried out experimentally with a completely randomized design (CRD). The treatments were given a dose of cod liver oil 0% (control), and the treatment 1-4 using a 3% increase each treatment dose. Analysis of data using ANOVA followed by Duncan test. Based on the research results giving cod liver oil on a commercial feed effect on increasing protein retention and energy retention of lobster meat. Retention of the best protein found in 4 treatments with a dose of 12%, while the retention of the best energy contained in the second treatment with a dose of 6%.

Litopenaeus vannamei is a leading commodity whose economic value. Targets of vannamei's production increasing every year. One of important factor in the success of shrimp farming is feed. Research about feed fish directed to the creation of feed fish whose economical and safe for the environment, therefore is required an efforts to provide alternative feed through feed supplement. One of the material that can be supplemented in feed is chitosan. Chitosan can increase the specific growth rate and protein retention of vannamei. This study aims to determine the effect of chitosan supplementation in commercial feed for specific growth rate and protein retention of Litopenaeus vannamei. The research method used was completely randomized design (RAL) and performed with five treatments chitosan supplementation (0%, 1%, 2%, 3% dan 4%) experimental animal used was ten shrimps as five replication in each treatment. The main parameters were observed are specific growth rate and protein retention of vaname. Supporting parameters were observed is water quality. The results showed that chitosan supplementation in commercial feed for 30 days of maintenance give an effect on the specific growth rate and protein retention of vaname. The highest specific growth rate was obtained in treatment with 4% chitosan supplementation that not significantly different with treatment 3% chitosan supplementation. Protein retention was incresed in treatment with 4% chitosan supplementation that not significantly different with treatment 3% chitosan supplementation.

The aim of the current trial was to test whether leucine affected growth and accretion including test any effects on leucine upon stress. Quadruplicate tanks each containing 50 Atlantic salmon (Salmo salar) (mean start body weight of 524 ± 28 g) were fed diets containing 27.3, 30.0, 35.0 and 41.0 g leucine/kg diet for 74 days. Two tanks per dietary group were exposed to a stressor (5 min chasing) three days a week to test whether enriched leucine diet aid coping with chronic stress, while two tanks per dietary groups were left unstressed. The stressed fish consumed less feed and grew less than the unstressed fish, irrespective of diet. Leucine inclusion did not affect protein accretion, but leucine retention declined with increasing dietary leucine in both stressed and unstressed fish. No difference between the stressed or unstressed fish was present. Leucine did not affect relative liver size, but unstressed fish had slightly higher relative liver size compared with stressed fish (p = 0.05). Free leucine in the muscle and liver was not affected by dietary leucine, but unstressed fish had higher concentration of valine and isoleucine in the muscle compared with the stressed fish. Muscle of fish fed elevated leucine had lower mRNA expression of murf1 (p = 0.037) and higher expression of ppara (p = 0.012). Muscle of stressed fish had higher expression of the oxydative genes mnsod (p = 0.049) and catalase (p = 0.037) compared with the fish left unstressed, while in liver, there were no differences of expression of any of the genes tested. In conclusion, diets enriched in leucine had minor effects and neither protein accretion nor growth was affected in either stressed or unstressed fish. [ABSTRACT FROM AUTHOR]

This study with juvenile rainbow trout evaluated the effects of dietary exposure to deoxynivalenol (DON) at industrially relevant doses (up to 1.6 mg/kg) on growth performance, the liver, and the gastrointestinal tract. Fifteen groups of 30 fish each were given one of five dietary treatments in triplicate: (1) control diet (CON; DON < 100 µg/kg feed), (2) naturally DON-contaminated diet (ND1) with a DON content of 700 µg/kg in the feed, (3) ND2 with a DON content of 1200 µg/kg feed, (4) a pure DON-contaminated diet (PD1) with 800 µg/kg of DON in the feed, and (5) PD2 with DON at a concentration of 1600 µg/kg in the feed. The feeding trial lasted eight weeks: six weeks of restrictive feeding followed by two weeks of ad libitum feeding. Exposure to DON during restrictive feeding for six weeks did not affect the growth performance of trout but did lead to a reduction in retained protein in fish fed with higher doses of DON in the ND2 and PD2 groups. During the two following weeks of ad libitum feeding, feed intake was similar among all groups, but body weight gain was lower in the ND2 and PD2 groups and feed efficiency was higher in PD2 (week 8). Histopathological assessment revealed liver damage, including altered nuclear characteristics and haemorrhages, in groups fed higher doses of natural DON (ND2) after just one week of restrictive feeding. Liver damage (necrosis and haemorrhage presence in ND2) was alleviated over time (week 6) but was again aggravated after ad libitum exposure (week 8). In contrast, gastrointestinal tract damage was generally mild with only a few histopathological alterations, and the absence of an inflammatory cytokine response was demonstrated by PCR at week 8. In conclusion, ad libitum dietary exposure of rainbow trout to either natural or pure DON resulted in reduced growth (dose-dependent), while restrictive exposure revealed time-dependent effects of natural DON in terms of liver damage.

A two‐phase feeding trial was conducted to estimate the dietary histidine requirement of juvenile and post‐juvenile rainbow trout for maximum growth and protein retention. Twelve isonitrogenous experimental diets were formulated where diet 1 was an 8% fishmeal basal diet having 0.5% histidine. Histidine was added to diets 2–6 to achieve levels of 0.7, 0.9, 1.1, 1.3 and 1.5% histidine respectively. Diets 7–12 were identical to diets 1–6 except for pellet size. In trial 1, fish (4 g) were fed test diets 1–6, and in trial 2, fish (40 g) were fed diets 7–12, to four replicate tanks per diet for 12 weeks. A nutrient digestibility trial was also conducted with trout from trial 2. Growth performance and feed utilization were not significantly influenced by dietary histidine supplementation above the basal diet level in either rainbow trout juveniles or post‐juveniles. Supplementation of histidine significantly increased protein and histidine digestibility, and it was lowest in the basal diet group. The highest histidine retention was in the lowest dietary histidine treatment group, and histidine retention progressively decreased at each increase in dietary histidine. In post‐juvenile trout, the same pattern was observed except that for the two lowest histidine levels, retention was similar and high. Finally, considering the overall growth and nutrient retention performances, the dietary histidine requirement is relatively higher in post‐juvenile trout (>0.6%) rather than juvenile trout (0.6%) under the present experimental conditions. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of lysine and histidine supplementation on growth performance, gene expression, blood parameters and quality of the fillet in Nile tilapia, Oreochromis niloticus (n = 192; 136.14 ± 2.32 g). Fish were distributed into four groups and fed a control diet without lysine and histidine supplementation (CON), supplemented with lysine (LYS), histidine (HIS) or lysine and histidine (LYS + HIS) and fed until apparent satiety for 90 days. Growth performance increased significantly in fish fed diet LYS + HIS (p <.05). The fillet body weight gain and fillet yield increased by 26.61% and 2.74% unit, respectively, compared to fish fed CON diet (p <.001). Compared to the control group, fish fed diets showed decreased whole‐body lipid and plasmatic triglycerides coupled to increased mRNA levels of MyoD and myogenin in the skeletal muscle and higher texture attributes of fillets (p <.05). There was a substantial negative correlation between body lipids and hardness of fillets. Overall, the combined supplementation of lysine and histidine optimizes growth performance, expression of muscle growth‐related genes and flesh quality attributes in grow‐out Nile tilapia. [ABSTRACT FROM AUTHOR]

Current parenteral containers used for the storage and delivery of protein-based drugs, contain silicone oil which may seep into the protein solution and can result in adsorption, aggregation and denaturation of the protein. Tightly adherent surface coatings prepared by radio frequency glow-discharge (RFGD) plasma polymerization are described in this paper. Using this robust technique, methacrylic acid (MA) (hydrophilic), hexamethyldisiloxane (HMDSO) (hydrophobic), tetraglyme (TG) (hydrophilic) were plasma polymerized onto glass. In addition, HMDSO and MA were copolymerized to create a plasma polymerized HMDSO-MA (hydrophobic) surface. Untreated glass and glass dip-coated in PDMS were used as controls. TG and MA plasma coatings adsorbed the least amount of protein in all pH conditions. Interestingly HMDSO-MA retained significantly lesser protein compared to HMDSO and dip-coated PDMS samples. In the presence of Polysorbate 80 (PS80) all plasma polymerized coatings adsorbed and retained negligible amounts of protein, compared to controls. Furthermore, the peak glide force of plasma coated syringes did not significantly increase compared to syringes without plasma coating. Due to the versatility of RFGD plasma, this process is scalable and could potentially be used for the treatment of hypodermic syringes used for the storage and delivery of protein-based therapeutics. [ABSTRACT FROM AUTHOR]

The efficiency of SID Lys utilization (kSID Lys) in gilts and sows during early (days 48 to 52), mid (days 75 to 79), and late gestation (days 103 to 107) was investigated using 88 pregnant females (PIC 1050; 27 gilts, 27 parity 1 sows, 34 parity 2+ sows; 192.96 ± 22.84 kg at days 42 ±1 of gestation) and whole body nitrogen (N) retention balance studies. Females were assigned to 1 of 4 SID Lys levels ranging from 40% to 70% of the daily SID Lys requirements above maintenance for a parity 1 sow according to the NRC (2012) gestating sow model in each gestation period. Experimental diets were isocaloric (3,335 kcal ME/kg) and isoproteic (11.75 % CP) and dietary indispensable AA were set to meet or exceed 100% of AA:Lys ratios. The slope of the linear response to graded SID Lys intake was defined as kSID Lys. With the aim of increasing the accuracy of kSID Lys estimates, gilt data from the current study was combined with gilt data from a previous study conducted at the same facility using 4 SID Lys levels ranging from 60% to 90% of the daily SID Lys requirements above maintenance for gilts according to the NRC (2012) gestating sow model. Whole body Lys retention of the combined gilt data set was assessed with different broken-line and nonlinear models. The kSID Lys was 0.65, 0.38, and 0.52 for early-, mid-, and late-gestation, respectively, in gilts. A linear response to graded SID Lys intake was found in late gestation only in parity 1 and 2+ sows; kSID Lys was determined as 0.44 and 0.52 in late gestation for parity 1 and parity 2+ sows, respectively. There were no differences in kSID Lys in late gestation between parities. For the combined gilt data, the model of best performance (reduced error and greater goodness of fit) was the Hoerl model. Maximum kSID Lys (i.e., g SID Lys retention/g SID Lys intake) in gilts was 0.67, 0.54, and 0.53 in early, mid, and late gestation predicted at 7.2, 9.1, and 13.5 g of SID Lys intake/d, respectively, based on the Hoerl model. Maximum SID Lys retention in gilts was similarly predicted at 8.5, 10.5, and 20.9 g of SID Lys intake per day in early, mid, and late gestation and resultant kSID Lys of 0.61, 0.51, and 0.44, respectively. The findings of this study demonstrate that kSID Lys varies by stage of gestation and SID Lys intake level and that, at least in gilts, a dynamic kSID adjusted for daily intake more adequately reflects biological response and hence allows more precise feeding of pregnant females. [ABSTRACT FROM AUTHOR]

Bariatric surgery may induce protein malabsorption, although data are scarce. This study aims at evaluating dietary protein bioavailability after different bariatric surgeries in rats. Diet-induced obese Wistar rats were operated for vertical sleeve gastrectomy (VSG) or Roux-en-Y gastric bypass (RYGB). The control group was composed of pair-fed, sham-operated rats (Sham). Two weeks after surgery, rats were fed a 15N protein meal. Protein bioavailability was assessed by determination of 15N recovery in the gastrointestinal tract and organs 6 h after the meal. Fractional protein synthesis rate (FSR) was assessed using a flooding dose of 13C valine. Weight loss was the highest in RYGB rats and the lowest in Sham rats. Surprisingly, RYGB (95.6 ± 0.7%) improved protein digestibility (P = 0.045) compared with Sham (93.5 ± 0.5%) and VSG (93.8 ± 0.6%). In contrast, 15N retained in the liver (P = 0.001) and plasma protein (P = 0.037) was lower than in Sham, with a similar trend in muscle (P = 0.052). FSR was little altered by bariatric surgery, except for a decrease in the kidney of RYGB (P = 0.02). The 15N distribution along the small intestinal tissue suggests that dietary nitrogen was considerably retained in the remodeled mucosa of RYGB compared with Sham. This study revealed that in contrast to VSG, RYGB slightly improved protein digestibility but altered peripheral protein bioavailability. This effect may be ascribed to a higher uptake of dietary amino acids by the remodeled intestine. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the efficiency of utilizing SID Lys and Thr for whole-body protein retention (kSIDLys and kSIDThr) in pregnant gilts. In Exp. 1, 45 gilts (158.0 ± 8.0 kg at day 39.4 ± 1 of gestation) in 2 groups were used in a 3-period nitrogen (N)-balance study. Gilts were assigned to 1 of 4 diets set to provide 60, 70, 80, and 90% of predicted daily SID Lys requirement for protein retention (NRC, 2012) in each of early (day 41 to 52, 10.44 g/d), mid- (day 68 to 79, 9.60 g/d), and late gestation (day 96 to 107, 16.04 g/d). Diets contained 3,300 kcal ME/kg and 11.6% CP; given at a rate of 2.13 kg/d in early and mid-gestation and at 2.53 kg/d during late gestation. The 12-d balance period (7-d adaptation; 5-d urine and fecal collection) was based on total urine collection using urinary catheters and determination of fecal N digestibility using indigestible marker. The SID Lys required for whole-body protein retention was estimated using the NRC (2012) model and the predicted Lys content of each gestation pool. Lysine efficiency at each diet Lys level was calculated as the ratio of daily Lys retention and SID Lys intake. The linear and quadratic response in whole-body N and Lys retention and Lys efficiency for each balance period was determined. The kSIDLys was determined from the slope generated by regressing whole-body Lys retention vs. SID Lys intake, with y -intercept set to 0. In Exp. 2, 45 gilts (165.7 ± 13.6 kg at day 39.1 ± 2 of gestation) were assigned to 1 of 4 diets set to provide 60, 70, 80, and 90% of the predicted daily SID Thr requirement for protein retention in each of early (6.46 g/d), mid- (6.05 g/d), and late gestation (9.75 g/d). Animal management, N-balance procedure, data collection and calculation, and statistical analyses were patterned from Exp. 1. In early and mid-gestation, whole-body N retention, as well as Lys and Thr retention, was not affected by the dietary SID Lys and Thr. In late gestation, there was a linear increase (P < 0.001) in whole-body N, Lys and Thr retention. The kSIDLys and kSIDThr in late gestation were determined to be 0.54. The lack of response in whole-body protein retention in early and mid-gestation may in partly reflect excess Lys and Thr intake. Lysine and Thr efficiency calculated at the lowest dietary Lys and Thr was 0.49 and 0.32 in early gestation and 0.61 and 0.52 in mid-gestation, respectively. Based on the available evidence, kSIDLys and kSIDThr do not appear to be constant throughout gestation. [ABSTRACT FROM AUTHOR]

Abstract To further optimize practical diets with respect to IAA requirements, this study was conducted to confirm and refine the tryptophan requirement, which is a potentially limiting AA in our matrix of ingredients. In order to ensure the best information on Trp requirement, our study used wide range of Trp levels and quality of fit of the models for calculating requirement estimates. Twelve iso‑nitrogenous and isoenergetic diets (practical defined ingredients) containing 30% protein and 8% lipid were formulated to meet the nutritional requirement of juvenile Nile tilapia (Oreochromis niloticus) with the exception of tryptophan. A basal diet deficient in tryptophan was assigned to meet all other known nutrient requirements of the Nile tilapia. L-tryptophan was then added to the basal diet at 0.04% increments to produce tryptophan levels ranging from 0.21 to 0.61% of the diet. The diet which supported the best performance of Nile tilapia in previous work, was used as a reference diet. Each diet was fed to three replicate groups of juvenile Nile tilapia (7.9 ± 0.1 g) in a recirculation system for eight weeks. Saturation kinetic model, broken line models with linear or quadratic ascending portions, were used to evaluate dose-response relationships of thermal-unit growth coefficient, apparent net protein retention, tryptophan retention against dietary tryptophan. Akaike weights were calculated and used for model selection in addition to the model's overall R 2. The tryptophan requirement of juvenile Nile tilapia was estimated at 0.31% (0.25–0.37%), 0.33% (0.26–0.39%), 0.25% (0.24–0.25%), 0.27% (0.25–0.31%) of the diet for optimum growth, tryptophan deposition, feed efficiency, and apparent net protein deposition (95% of maximum value), respectively. Highlights • The study was conducted using Nile tilapia to confirm and refine the tryptophan requirement, which is a potentially limiting AA in our matrix of ingredients. • Saturation kinetic model, broken line models with linear or quadratic ascending portions, were used to evaluate dose-response relationships of thermal-unit growth coefficient, apparent net protein retention, tryptophan retention against dietary tryptophan. Akaike weights were calculated and used for model selection in addition to the model's overall R 2. • The tryptophan requirement of juvenile Nile tilapia was estimated at 0.31% (0.25–0.37%), 0.33% (0.26–0.39%), 0.25% (0.24–0.25%), 0.27% (0.25–0.31%) of the diet for optimum growth, tryptophan deposition, feed efficiency and apparent net protein deposition (95% of maximum value), respectively. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the nutritional value of pasta enriched with legume or wheat gluten proteins and dried at varying temperature. A total of four isonitrogenous experimental diets were produced using gluten powder/wheat semolina (6/94, g/g) pasta and faba bean flour/wheat semolina (35/65, g/g) pasta dried at either 55°C (GLT and FLT, respectively) or 90°C (FVHT and GVHT, respectively). Experimental diets were fed to ten 1-month-old Wistar rats (body weight=176 (sem 15) g) for 21 d. Growth and nutritional, metabolic and inflammatory markers were measured and compared with an isonitrogenous casein diet (CD). The enrichment with faba bean increased the lysine, threonine and branched amino acids by 97, 23 and 10 %, respectively. Protein utilisation also increased by 75 % (P <0·01) in FLT in comparison to GLT diet, without any effect on the corrected faecal digestibility (P >0·05). Faba bean pasta diets' corrected protein digestibility and utilisation was only 3·5 and 9 %, respectively, lower than the CD. Growth rate, blood composition and muscle weights were not generally different with faba bean pasta diets compared with CD. Corrected protein digestibility was 3 % lower in GVHT than GLT, which may be associated with greater carboxymethyllysine. This study in growing rats clearly indicates improvement in growth performance of rats fed legume-enriched pasta diet compared with rats fed gluten–wheat pasta diet, regardless of pasta drying temperature. This means faba bean flour can be used to improve the protein quality and quantity of pasta. [ABSTRACT FROM AUTHOR]

An 8‐week feeding trial was conducted to investigate the dietary protein requirement of juvenile mandarin fish, Siniperca scherzeri, a demersal freshwater piscivore with high commercial value in East Asia. Five isolipidic (100 g/kg) and isoenergetic (20 MJ/kg) practical diets were formulated to contain graded levels of 450, 500, 550, 600, and 650 g/kg crude protein, using mackerel fishmeal as the sole source of protein. Each of the five test diets was fed to visual satiety to triplicate groups of fish (initial mean body weight ± SE; 20.1 ± 0.2 g) reared in a recirculating freshwater system over the experimental period. Fish growth performance in terms of weight gain tended to improve with increasing dietary protein level, and the highest values were observed in those fish fed the 600–650 g/kg diets. Feed intake significantly declined as the protein content of the diet increased. Feed efficiency and protein retention tended to increase with increasing dietary protein levels, from 450 to 600 g/kg, and then declined when dietary protein content further increased to 650 g/kg. A similar trend was also found for the protein efficiency ratio, although the observed changes did not reach statistical significance. Whole‐body composition and plasma biochemical parameters were not significantly affected by the dietary protein content. Based on these findings and a broken‐line model of growth, 614.4 g/kg seems to be the proper amount of protein in a practical diet for >20 g mandarin fish. [ABSTRACT FROM AUTHOR]

The research was conducted to know the effect and to determine the best utilization of the chiken feather silage meal as a substitute for fish meal protein source in the feed formula of Colossoma macropomum. This study used experimental method based on Completely Randomized Design (CRD) with 5 treatments and 3 replications. Five diets (33% isoprotein and 3.85 kcal/g diet isoenergi) were formulated with substitution of the chiken feather silage meal to fishmeal protein. These substituted 0, 25, 50, 75 and 100 % (A, B, C, D and E respectively) of the fishmeal protein. Parameters observed and analyzed were: survival rate, specific growth rate, feed conversion ratio, protein efficiency ratio, protein retention and protein digestibility. The results showed that the treatment had no effect on survival rate, specific growth rate, feed conversion ratio, protein efficiency ratio, and protein retention but the effect on protein digestibility. Based on these results, it can be concluded that fishmeal protein can be substituted with the chiken feather silage meal up to 100% in the feed formula of Colossoma macropomum.

Two trials were conducted to determine net protein requirements and the use of metabolizable protein (MP) for growing ram lambs when fed diets with different concentrate levels and roughage quality. In a comparative slaughter trial, eighty-four ½ Dorper × ½ Santa Inês ram lambs (18.0 ± 3.3 kg of BW) were individually penned and divided into 2 diet groups differing in roughage source: low-quality (sugarcane bagasse) roughage (LQR) or medium-quality (coastcross hay) roughage (MQR). In each group, 7 lambs were randomly selected and slaughtered after a 10 days adaptation period (baseline). Other 21 lambs from each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg of BW, and the remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction (70 or 50% of the ad libitum intake). Body N content and retention were determined. In the second trial, 6 ram lambs (44.3 ± 5.6 kg of BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to determine N digestibility and microbial N synthesis, and to compute MP supply by the 2 diets and 3 levels of intake. Nitrogen intake and microbial N synthesis were greater for the animals fed the MQR diet than for those fed the LQR diet ( P  < 0.05). Neither the endogenous and metabolic N losses, nor the net protein requirements for growth differed between diets ( P  > 0.05). However, the proportion of MP used for both maintenance and growth was lower for the animals fed the MQR diet ( P <  0.05), likely because of an excess of MP reaching duodenum of these animals. We concluded that a reduction of the concentrate level in diets for growing ram lambs, achieved by improving the quality of the diet roughage, allows a greater supply of MP and may contribute to reduce diet protein concentration. [ABSTRACT FROM AUTHOR]

Abstract: In this study, two different dietary protein levels were tested (500 and 600 g/kg) in meagre juveniles of approximately 2 g, to determine whether a higher body protein diet would favour muscle growth. Results showed that meagre survival and growth were not affected by different levels of dietary protein. However, a higher content of protein was observed in the body composition of meagre fed the P60 diet (656 g/kg versus 624 g/kg). When fish were 82 days after hatched (DAH), protein retention efficiency was significantly higher in fish that were fed the P50 diet (37.1% versus 32.5%). Muscle cellularity changed considerably from the beginning to the end of the trial. The contribution of fibre hyperplasia to muscle growth was reduced although still accounted for 30% in 96 DAH meagre. Several differences were found in the frequency of fibres with areas between 1,000 μm2 and 2,200 μm2 between younger and older meagre, but no effect was found associated with dietary protein. This study suggests that neither growth nor muscle cellularity of fast‐growing juvenile meagre is positively affected by an increased dietary protein levels. [ABSTRACT FROM AUTHOR]

A 12 week growth study was carried out to investigate the supplemental effects of dietary garlic powder (GP) on growth, feed utilization and whole body composition changes of fingerling sterlet sturgeon Acipenser ruthenus (averaging weight, 5.5 g). Following a 24-h fasting, 540 fish were randomly distributed to each of 18 tanks (30 fish/tank) under a semi-recirculation freshwater system. The GP of 0.5% (GP0.5), 1% (GP1), 1.5% (GP1.5), 2% (GP2) and 3% (GP3) was added to the control diet (GP0) containing 43% protein and 16% lipid. After the feeding trial, weight gain (WG) of fish fed GP1.5, GP2 and GP3 were significantly higher (p

Methionine-choline-deficient ( MCD) mammals are known to accumulate liver TAG probably due to phosphatidylcholine ( PC) deficiency and thus assembly of VLDL and transport of lipids from liver to peripheral organs. To assess whether supplementation of choline could spare methionine and secure a healthy liver metabolism, by reducing the endogenous PC synthesis without interfering with lipid transport and distribution, Atlantic salmon with initial BW of 700 g were fed adequate (1.9 g Met/16 gN) or surplus methionine (2.5 g Met/16 gN) diets of which were supplemented with choline or not for a period of 19 weeks. Fish fed the low-methionine diets had reduced growth ( p = .013) due to reduced protein gain ( p = .007), while lipid gain slightly improved in fish fed the choline-supplemented diets ( p = .047). Also, feed conversion improved when fed surplus methionine ( p < .001), while choline supplementation had no impact on feed conversion. No interaction between choline and methionine on growth performance or retention existed. Phospholipid status in liver and muscle was not affected by treatments, and no liver TAG accumulation occurred at the methionine levels used. Gene expression of ApoB100 necessary for assembling VLDL or pemt necessary for endogenous PC synthesis was unaffected by treatments. Capacity of methylation ( MAT, BHMT) within the liver was not affected by treatment nor was the gene expression of enzymes in liver transsulfuration ( CBS or CDO). Methionine status within liver was unaffected by treatments, while free methionine reduced in those fish fed the low-methionine diets in muscle and plasma. Cystathionine and taurine were elevated when fed surplus methionine. Choline supplementation had no impact on sulphur amino acid metabolites in either tissue. Neither did choline supplementation improve TAG mobilization from liver to muscle. To conclude, choline does not improve endogenous phospholipid synthesis or transport of TAG from liver to muscle depot when added to diets containing 1.9 g Met/16 gN, while surplus methionine improved growth and protein retention, indicating that 1.9 g Met/16 gN is enough to support a healthy liver metabolism, but too low to support muscle protein deposition in adult salmon fed high plant protein diets for longer periods of time. [ABSTRACT FROM AUTHOR]

The purpose of this work was to evaluate the effect of the temperature (50 and 60 °C) of a NaOH cleaning solution during the diafiltration of a binary mixture of bovine serum albumin and β-lactoglobulin, through a 300 kDa tubular ceramic membrane along repeated operational cycles. To this aim, final permeate volume, membrane and fouling resistances and individual protein concentration were analyzed. At the end of each individual study, the membranes were characterized by liquid-liquid displacement porosimetry. As a result, 50 °C was found to be the most appropriated temperature due to its higher capability to restore the initial membrane resistance and the higher efficiency achieved in terms of protein separation. Both conditions fulfilled without altering the structural properties of the membrane as given by porosimetric analysis. In contrast, a great fouling resistance involving null protein transmission occurred when cleaning was performed at 60 °C. [ABSTRACT FROM AUTHOR]

Fed-batch and perfusion cell culture processes used to produce therapeutic proteins can use microfilters for product harvest. In this study, new explicit mathematical models of sieving loss due to internal membrane fouling, external membrane fouling, or a combination of the two were generated. The models accounted for membrane and cake structures and hindered solute transport. Internal membrane fouling was assumed to occur due to the accumulation of foulant on either membrane pore walls (pore-retention model) or membrane fibers (fiber-retention model). External cake fouling was assumed to occur either by the growth of a single incompressible cake layer (cake-growth) or by the accumulation of a number of independent cake layers (cake-series). The pore-retention model was combined with either the cake-series or cake-growth models to obtain models that describe internal and external fouling occurring either simultaneously or sequentially. The models were tested using well-documented sieving decline data available in the literature. The sequential pore-retention followed by cake-growth model provided a good fit of sieving decline data during beer microfiltration. The cake-series and cake-growth models provided good fits of sieving decline data during the microfiltration of a perfusion cell culture. The new models provide insights into the mechanisms of fouling that result in the loss of product sieving. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1323-1333, 2017 [ABSTRACT FROM AUTHOR]

Two experiments were conducted to study the possibility of utilizing enzyme incubated rape seed meal (RSM) in broiler diets (1 to 42 day of age). The RSM was anaerobically incubated with non-starch polysaccharide hydrolyzing enzymes (cellulase 1,500 IU, xylanase 250 IU and pectinase 125 IU per kilogram) for 300 minutes (processed RSM1, experiments 1 and 2) and 600 min (processed RSM2, experiment 2). Processed and raw RSM contained similar concentration of glucosinolates (275 and 288 mM/g, respectively). During the experiment 1, maize-soybean meal control diet (CD), two diets with raw (RRSM) and processed RSM (PRSM1) at 100 g/kg each were prepared. In the experiment 2, RRSM, PRSM1 and PRSM2 were included each at 3 levels (50, 100 and 150 g/kg). Each diet was offered to 9 replicates having 5 birds in each. Body weight gain (BWG), feed intake (FI), feed efficiency (FE), ready to cook (RTC) yield and breast weight were depressed by incorporating RRSM (experiments 1, 2). As a result of this study, PRSM1 significantly reduced FI, maintained BWG and improved FE compared to the control group. BWG was not affected by including PRSM1 and PRSM2 up to 100 and 50 g/kg, respectively but depressed at higher inclusion levels compared to the CD. The BWG in processed RSM fed groups were higher than the respective level of raw RSM fed groups. Retention of energy and protein were improved by incorporating processed RSM compared to those fed RRSM. Based on the data, it is concluded that enzyme (cellulase, xylanase and pectinase) incubated RSM for 300 minutes improved the nutritional value, which can be incorporated up to 100 g/kg in broiler diet without affecting performance and slaughter variables, which can be attributed to the improved retention of energy and protein in RSM based diets. [ABSTRACT FROM AUTHOR]

Proper nutrient management is essential for the environmental sustainability of aquaculture. While increasing daily rations generally may lead to improved growth rates, this does not necessarily mean that nutrients are utilized more efficiently. To investigate how ration size affects partitioning of dietary nutrient intake, the effects of meal size on growth and metabolism were examined in triplicate groups of adult Nile tilapia ( Oreochromis niloticus ) receiving daily rations corresponding to 1, 2, 3, or 4% of their biomass. While biomass gain and specific growth rates were positively correlated with ration size, feed conversion and protein retention were most efficient at ration sizes of 3%. Although the magnitude of the SDA response following feeding also increased with ration size, this was not proportionate to meal size. Therefore the metabolic cost of meal processing (SDA coefficient) was found to be lowest in the 3% ration group. The lowest rates of nitrogen excretion as well as the lowest SDA coefficients were also observed for fish receiving meal sizes corresponding to 3% of their body mass. In contrast, fish fed ration sizes of 1% displayed a reduction in apparent digestibility of protein, nitrogen free extract and dry matter, in addition to excreting a disproportionate amount of ingested nitrogen as ammonia and urea. [ABSTRACT FROM AUTHOR]

The objective of the research was to know the best method of processed-shrimp wastes on protein consumption and retention. Experiment was designed using completely randomized design with five treatments of ration and four replications. Treatments were basal ration with added by 5% shrimp waste. Treatments were D0 (basal diet + non treated shrimp waste), D1 (basal diet + shrimp waste hydrolyzed by 3% NaOH), D2 (basal diet + shrimp waste hydrolyzed by 6% NaOH), D3 (basal diet + shrimp waste hydrolyzed by 5% H2O2), and D4 (basal diet + shrimp waste fermented by Aspergillus niger). The total number of treated chicken was 20 broiler of MB 202 strain. To compare the effect of treatments, data was analyzed using least square difference. Results showed that the treated shrimp waste had potential to use as protein source in broiler diet and the best consumption and retention protein was found in hydrolysis shrimp waste by 3% NaOH and 5% H2O. (Animal Production 12(1): 1-5 (2010)Key Words: shrimp waste, protein consumption, protein retention, broiler, Aspergillus niger

Nutritional requirements of the Iberian pig, a slow-growing, obese porcine breed, are not well defined and seem to differ from those of conventional or high-performing pigs. The effects of the dietary protein content and the feeding level on the utilisation of metabolisable energy (ME) and the rates of gain, protein, and fat deposition were studied with 81 Iberian castrates growing from 50 to 100 kg body weight (BW) by using the comparative slaughter technique. The animals were fed 4 diets providing 145, 120, 95, and 70 g ideal crude protein (CP) per kg dry matter (DM), and containing 13.94, 14.29, 14.56, and 14.83 MJ ME per kg DM, respectively. Three levels of feeding were evaluated: 0.60, 0.80, and 0.95 × ad libitum intake. Growth rate increased (linear and quadratic, P

The study was conducted using channel catfish and tilapia to evaluate the production performance of these fish to increasing levels of lysine from crystalline and intact lysine supplemented in practical diets. A practical lysine deficient basal diet was developed using corn protein concentrate (Empyreal® 75) as a primary protein source. To this diet either graded levels of crystalline lysine or similar levels from a high lysine corn protein concentrate (Lysto™) were added. In the channel catfish trial, the first five diets were designed to contain increasing levels of crystalline lysine (1.21%, 1.34%, 1.45%, 1.56%, and 1.72%) with an additional four diets using intact protein from a high lysine corn protein concentrate (1.40%, 1.57%, 1.77%, and 1.91% lysine). In the tilapia trial, lysine from two sources was added to 11 diets to produce analyzed lysine levels of 0.92%, 1.11%, 1.23%, 1.34%, 1.54% 1.65% in the first six diets using crystalline lysine and 1.13%, 1.38%, 1.61%, 1.81%, 2.02% in the last five diets using intact lysine. Results indicated that channel catfish and tilapia have positive performance with increasing lysine supplementation up to the requirement. Fish fed with the higher levels of lysine had the highest weight gain and lowest feed conversion ratio. The regression analysis on the increased level of inclusion of crystalline lysine and intact lysine showed no significant difference in slope. Based on the growth, feed conversion ratio and apparent net protein retention data obtained from this study, it can be concluded that the effectiveness of using intact lysine via high lysine corn protein concentrate as a lysine supplement is not significantly different from crystalline lysine. Thus, the high lysine corn protein concentrate is a feasible ingredient for aquaculture feeds, which can be used to balance the amino acid composition of the diet without addition of crystalline lysine. Statement of relevance Present study shows that high lysine corn protein concentrate is a feasible ingredient for aquaculture feeds, which can be used to balance the amino acid composition of the diet without addition of crystalline lysine. [ABSTRACT FROM AUTHOR]

Four diets were formulated to evaluate the partial to total substitution of fishmeal with poultry by-product meal ( PBM) (0, 33, 67 and 100 PBM) in diets for totoaba juveniles ( Totoaba macdonaldi). Amino acid profiles from diets and fatty acid content in diets and muscle tissue were used to assess the fish performance using PBM as fishmeal replacement. Stable isotopes of nitrogen (δ15N) were measured in muscle and liver tissue to quantify the retention of each protein source. At the end of the experimental period, the fish fed the 67 PBM diet had a significantly higher growth gain increase compared to the other treatments (almost 2000% over an 86 days period; TGC of 1.06). The total replacement of fishmeal with PBM led to low growth gain increase (ca. 220% over 72 days; TGC of 0.52) and increased mortality. Both fish performance and tissues' fatty acid composition suggest that the 100 PBM diet was deficient in essential fatty acids. An isotope-mixing model applied to isotope ratios of muscle and liver tissues of fish fed the 67 PBM tissues indicated that PBM was retained into muscle and liver tissue in a higher proportion than its level of inclusion in the diet. We conclude that PBM is a good source of nutrients for totoaba juveniles when used in up to 67% fishmeal replacement level in diets containing 52% protein leading to adequate growth rate and survival. [ABSTRACT FROM AUTHOR]

This study compares growth, intake and retention efficiencies of nutrients and energy between common sole ( Solea solea L.) fed ragworm ( Nereis virens, Sars), blue mussel ( Mytilus edulis L.) and an artificial (commercial) feed. Food types were fed to common sole (mean initial body weight: 44.9 ± 2.3 g) in excess three times a day over a 54-day-period. The growth rate in common sole fed the natural prey (8.5 g kg−0.8 d−1) was significantly higher compared to the growth rate in fish fed the artificial feed (5.1 g kg−0.8 d−1). Nutrient and energy intake was significantly lower in common sole fed the artificial feed than in fish fed natural prey. The only exception was fat intake which was higher in common sole fed the artificial feed in contrast to fish fed the natural prey. Nutrient and energy retention efficiencies were significantly lower in common sole fed the artificial feed than in fish fed the natural prey. In conclusion, the low growth in common sole fed the artificial feed was related to lower nutrient and energy intake as well as lower nutrient and energy retention efficiencies. It is suggested that reduced intake of the artificial feed might be related to the high dietary fat content of the artificial feed. [ABSTRACT FROM AUTHOR]

To enhance the biocompatibility or extend the biomedical application of poly(caprolactone) (PCL), protein retention on PCL surface is often required. In this study, poly(acrylamide) (PAAm) brushes were grown from PCL surface via surface-initiated atom transfer radical polymerization (SI-ATRP) and served as a protein-capturing platform. Grafted PAAm was densely packed on surface and exhibited superior protein retention ability. Captured protein was found to be resistant to washing under detergent environment. Furthermore, protein structure after being captured was investigated by circular dichroism (CD) spectroscopy, and the CD spectra verified that secondary structure of captured proteins was maintained, indicating no denaturation of protein happened for retention process. [ABSTRACT FROM AUTHOR]

The suitability of land animal by-products (ABPs) in feed for Atlantic salmon postsmolts (initial weight 372 g) in sea water was studied in a feeding experiment, using poultry by-product meal (PBM) and porcine blood meal (BM) as protein sources and poultry oil as fat source. Four extruded feeds were tested in a 2 * 2 factorial model, with or without ABP protein sources and with or without poultry oil. The control feed contained a mix of marine and plant ingredients. Initial feed intake was highest in the ABP protein-based diets, whereas poultry oil had a weak opposite effect. No differences were seen in growth rate or body weight. Addition of PBM and BM led to increased FCR, and lower retention of crude protein and energy. This could be explained by lower digestibility of amino acids and crude protein, and a slightly lower energy level in these diets. Reduced igf1 mRNA levels in liver and muscle were seen in fish fed dietary ABP protein and oil. Despite lower protein digestibility of ABP protein, this study confirms the suitability of ABP protein and lipid in combination with plant ingredients in feed for Atlantic salmon growers. [ABSTRACT FROM AUTHOR]

A factorial experiment was conducted with black tiger shrimp ( Penaeus monodon ) juveniles to determine the effects of varying protein inclusion in the diet and also varying inclusion of a microbial biomass on growth, feed and nutrient utilization when fed in indoor laboratory conditions. The growth performance of the shrimp improved with increasing diet protein level. However, in the absence of the added microbial biomass, this growth performance plateaued at the 480 g/kg protein level. The addition of the microbial biomass improved growth at each inclusion level of both protein and microbial biomass. No plateau in growth was observed with the addition of the microbial biomass. Improvements in feed conversion were seen with increasing dietary protein levels and also the inclusion of the microbial biomass. Examination of the feed intake of each treatment supports that there was a combined effect of an increase in feed intake and improvements in feed conversion that contributed to the improvements in growth performance with the use of the microbial biomass, but the increases in dietary protein level largely influenced growth through improvements in feed conversion. [ABSTRACT FROM AUTHOR]

The present study evaluates the effect of dietary glutamate and glutamine supplementation on growth performance, body composition and expression of key enzymes involved in the hepatic metabolism of juvenile gilthead seabream ( Sparus aurata ). Fish were fed for 52 days with four diets, which were identical in composition except for a 4% supplementation with glutamate (GLU diet), glutamine (GLN diet), carbohydrate (CHO diet) or bovine serum albumin (BSA diet). Glutamate and glutamine supplementation improved feed conversion ratio and protein retention compared to carbohydrate supplementation, and, in the case of glutamate, protein retention was improved over that of fish fed the protein supplemented diet. Feeding CHO and GLU diets resulted in up-regulation of glucokinase and lipogenic enzymes compared to fish fed GLN and BSA diets. Consistently, fish fed CHO or GLU diets showed higher triglyceride levels in serum and liver, and feeding the GLU diet resulted in higher body fat content than in fish fed GLN or BSA diets. The liver of fish fed GLN or BSA diets showed increased glutamate dehydrogenase activity in the direction of the glutamate oxidation. In contrast to fish fed the BSA diet, increased glutamate oxidation did not reduce free glutamine and glutamate levels in the liver of fish fed the GLN diet, suggesting that glutamine intake exceeded liver's energy requirements. In conclusion, glutamate supplementation improved hepatic glucose metabolism, whereas supplemented glutamine seems to be preferentially oxidized over amino acids derived from dietary protein, thus promoting higher protein retention in both cases. Our findings indicate that glutamate and glutamine could partly replace dietary protein and that glutamate supplementation could also facilitate protein replacement by carbohydrates in fish feeds. [ABSTRACT FROM AUTHOR]

Fish appear to have a limited capacity for digesting complex proteins during the early life stages. A better understanding of fish larvae protein digestive capacity and subsequent metabolic utilisation (amino acid (AA) catabolism and retention), depending on dietary protein molecular weight (MW) and larval development stages, is essential for developing formulated microdiets suited to larval requirements throughout ontogeny. The aim of this work was to develop a method enabling the in vivo production of radiolabelled polypeptides and protein fractions of different MW using Artemia metanauplii , and apply this new tool to assess protein digestive capacity and evaluate protein metabolic utilisation (catabolism and retention) throughout ontogeny of Senegalese sole larvae. Characterisation of MW distribution of Artemia protein content by size exclusion chromatography at different time points after hatching showed that from hatching to 24 h post-hatching (hph), the profile is dominated by polypeptides and proteins having a MW in the ranges 0.5–1.9 kDa, 2.8–7.0 kDa and above 476 kDa. At 36 hph a shift from high MW proteins to lower MW polypeptides was observed in the elution patterns. Fractions of radiolabelled polypeptides and proteins of various MW were produced through in vivo labelling of A. metanauplii , by incubation in a [U– 14 C] free AA mixture, and subsequent separation of Artemia proteins according to their MW by size exclusion chromatography. Digestibility and metabolic utilisation of some of the radiolabelled polypeptide fractions obtained (fractions of 1.0 kDa and 6.8 kDa) were assessed throughout Senegalese sole larval development (12, 21 and 34 days after hatching (DAH)) fed on live feed, through the controlled tube-feeding methodology combined with metabolic chambers. The results showed that the polypeptide fraction of 1.0 kDa was highly digestible and similarly retained in larval body at all developmental stages assayed. Conversely, the 6.8 kDa polypeptide fraction was poorly absorbed by young larval stages (12 DAH) but absorption improved throughout larval development (from 12 to 34 DAH). Body retention efficiency of the 6.8 kDa polypeptide fraction tended also to increase (and catabolism rate tended to decrease) throughout ontogeny, displaying a positive correlation (Spearman's correlation) with larval age. The method we report here is novel and may constitute a useful tool to assist in defining the most suitable MW range of proteins to incorporate into larval diets, for different developmental stages of Senegalese sole and other teleost larvae. [ABSTRACT FROM AUTHOR]

The objectives of this study were to further optimize balance of dietary amino acids (AA) offered to Nile tilapia by investigating the role of dispensable AA (DAA) across the range of indispensable AA (IAA) intakes. The possible limitation of IAA intake in fish consuming diets with high inclusion of crystalline AA (CAA) supplemented to the diets was also confirmed. The basal diet was formulated to contain 22.2% intact protein in which IAA were adjusted to reach 100%, 110% and 120% of NRC requirements with or without DAA supplementation. Glycine and glutamic acid were used as DAA sources at 1:1 and 2:2 ratio to assign 2 levels of DAA at 2% and 4% of the diet. Fish were hand sorted to a uniform size then randomly stocked into 44 aquaria with 15 fish per/tank. Fish were fed 4 times a day to near satiation over a 10-week period. To evaluate feeding regimes on CAA utilization diets with 100% IAA without DAA supplements and 110% IAA with 4% DAA supplements were paired and fed to fish using 2 and 4 feedings per day. Results confirmed that DAA contribute to meeting the nitrogen requirement of fish in which fish fed diets with DAA supplementation had significantly higher growth rates (thermal-unit growth coefficient, TGC) and lower FCR compared to fish fed diets without DAA supplementation. Growth of fish fed diets without DAA supplementation was not comparable to fish fed diets supplemented with DAA irrespective of IAA supplements up to 120% NRC requirement. Fish fed diets with DAA supplements at 4% exhibited superior growth compared to fish fed diets with 0% and 2% DAA supplements. The supplementation of IAA at 110% NRC requirement helped the fish have better growth compared to fish fed diets formulated to 100% NRC. However, no further benefit was observed on growth performance of fish fed diets with IAA supplements up to 120%. Fish fed diets with IAA supplements at 110% NRC and 4% DAA supplements exhibited the best response. The results of this study indicated that although DAA provided benefits in balancing AA profiles of feed, limitation of IAA intake at 100% NRC might cause impaired growth of Nile tilapia. In addition to this, no influence of feeding frequency was obtained on growth performance of fish feed, suggesting that fish can be fed successfully two times per day regardless of high inclusion levels of CAA. • The important role of DAA in meeting the nitrogen requirement of Nile tilapia is confirmed in which DAA inclusion rate of 4% of the diet offering the best performance of fish. • The result of this study also indicates the inferior growth of fish fed diet with IAA supplements at 100% NRC requirements which might result from limitation of daily IAA intake. • Fish can be fed successfully two times per day regardless of high inclusion levels of crystalline amino acid. [ABSTRACT FROM AUTHOR]

A 9-week feeding trial was carried out to evaluate dietary arginine requirement of juvenile red sea bream. Six isonitrogenous and isocaloric diets (50% crude protein and 17.7 kJ g − 1 gross energy) were formulated to contain graded levels of arginine including 1.42, 1.88, 2.22, 2.54, 3.08 and 3.43% of diet (2.84–6.86% of dietary protein), and fed triplicate groups of fish (13.3 ± 0.2 g) to apparent satiation twice daily. At the end of the feeding trial, fish fed ≥ 2.22% arginine showed significantly ( P < 0.05) higher growth than those fed 1.42% arginine. Significant improvement in protein productive value was found at dietary arginine level of 2.54% compared to the fish fed 1.42% arginine. Significant reductions in whole-body and muscle lipid contents were found by increment of arginine level and whole-body protein increased significantly in fish fed 2.22–2.54% arginine compared to those fed 1.42% arginine. Plasma total protein level significantly was increased in fish fed 2.54–3.08% arginine, and alanine aminotransferase activity and glucose level were significantly decreased in fish fed 2.22–2.54% and ≥ 1.88% arginine, respectively, compared to the group fed 1.42% arginine. Significant improvements in lysozyme and myeloperoxidase activities and total immunoglobulin level were obtained by dietary arginine increment. Also, significantly higher total nitric oxide synthase activity was recorded at 3.08% arginine level in comparison to 1.42% arginine. A broken-line regression analysis on weight gain showed that the optimum dietary arginine level is 2.37% of diet (4.74% of dietary protein). [ABSTRACT FROM AUTHOR]

Amino acids are vital for all living organisms including fish and histidine is an essential amino acid for fish. In view of this, dietary histidine requirement of fry Heteropneustes fossilis was determined by feeding casein-gelatin-based isonitrogenous (430 g kg−1 CP) and isocaloric (17.9 MJ kg−1 GE; 15.5 MJ kg−1 DE) amino acid test diets (10 to 20 g histidine kg−1 dry diet) to quadruplicate groups of randomly assigned fish to apparent satiety for 12 weeks. Maximum absolute weight gain (AWG; 44 g fish−1), protein retention efficiency (PRE; 20%), protein efficiency ratio (PER; 1.04), haemoglobin (Hb; 11.24 g dL−1), haematocrit (Hct; 35.11%), red blood count (RBCs; 2.98 × 109 mL−1) and lowest erythrocyte sedimentation rate (ESR; 1.92 mm h−1) were obtained at 16 g histidine kg−1 dry diet. The 95% maximum quadratic response of above data exhibited the requirement to be at 15.2, 15.1, 15.6 and 15.5 g histidine kg−1 diet. As histidine is found in higher concentration in haemoglobin, requirement obtained for Hct% and Hb is 4% greater than that required for maximizing weight gain and protein retention. Based on these results, dietary histidine requirement of H. fossilis fry is recommended between 15.1 and 15.6 g kg−1, corresponding to 35.1-36.3 g kg−1 protein. [ABSTRACT FROM AUTHOR]

The lack of specific compound diets for cephalopods is limiting the industrial development of some species. In this study, four agglutinated moist diets were tested in individually reared Octopus vulgaris (979 ± 151 g) for 8 weeks. All diets were based on bogue Boops boops, accidentally reared in fish farms (aquaculture by-product), and agglutinated with alginate and calcium. One diet was based exclusively on bogue fillets, two on bogue fillets complemented with meat from two crab species ( Portunus pelagicus, Grapsus grapsus) and the last one on bogue and G. grapsus meals. As a control diet, bogue and P. pelagicus were supplied fresh on alternate days. All diets induced similar feed intake (2.1-2.6% day−1). However, the meal-based diet induced negative growth in comparison with the control and the other agglutinated diets (0.80-0.85% day−1). Higher lipid content in agglutinated diets (28-30% dw) in comparison with the control diet (16% dw) led to higher protein retention in muscle. These results underline the inadequacy of traditional meals in diets for cephalopods and that the inclusion of crab meat did not increase feeding rates and growth in O. vulgaris. The dietary fatty acid, with high levels of oleic and linoleic acid and low levels of ARA, clearly reflected in digestive gland, while only decreasing ARA and increasing EPA levels were observed in muscle, with no apparent negative effect on growth. [ABSTRACT FROM AUTHOR]