Growth performance and feed efficiency of Asian redtail catfish (Hemibagrus nemurus) larvae in response to dietary shrimp protein hydrolysate

A shrimp protein hydrolysate (SPH) containing 894.2 g kg−1 crude protein (CP) and 54.3 g kg−1 total lipids was tested as a partial replacement for fish meal (FM) in diets of juvenile cobia. The effects of increasing dietary levels of SPH on the survival, weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), nitrogen retention efficiency (NRE) and daily feed intake (DFI) of cobia with initial body weight of 11.9 g were evaluated. Four isoproteic (from 431.1 to 439.7 g kg−1) and isoenergetic (20 825–21 347 MJ kg−1) diets were formulated to contain 0 (Control), 120, 240 or 360 g kg−1 of dietary CP derived from SPH. Survival, WG, SGR, FCR, NRE and DFI ranged from 90 to 100%, 40.2–56.5 g, 4.7–6.1% day−1, 1.04–1.54, 26.3–44.0% and 4.7–6.0% fish−1 day−1 respectively. Survival and DFI were not affected by the dietary treatments. On the other hand, fish fed the control diet and the one containing 120 g kg−1 SPH had higher WG, SGR and FCR. Nitrogen retention efficiency was significantly higher for fish fed diets 0 and 120. It is concluded that up to 120 g kg−1 of SPH in cobia diets can be used with no significant effects on feed utilization and fish performance.

Protein hydrolysates are known for their feed attractant properties in various fish species; however, their efficacy in the Asian redtail catfish (Hemibagrus nemurus) remains underexplored. This study evaluated the effects of shrimp head protein hydrolysate (SHPH) on feed attractiveness and palatability in the Asian redtail catfish larvae. A completely randomized design was employed, incorporating four dietary treatments: a control (0% SHPH) and three experimental diets with 2.5, 5, and 7.5% SHPH supplementation, respectively. Larval responses were analyzed, including the attractiveness and palatability of the larval feed, the level of feed consumption, feed efficiency, feed rejection, and the time to first feed capture. Results demonstrated significant effects on feed attractiveness and palatability when SHPH was included in the diets. The treatment with 5% SHPH supplementation produced the most favorable outcomes across all measured parameters. These findings suggest that SHPH can significantly enhance the feeding responses of the Asian redtail catfish larvae, with a 5% inclusion level in the diets being the most optimal dose. Incorporating SHPH into the larval diets of the Asian redtail catfish has the potential to improve feed utilization and minimize waste, contributing to more sustainable aquaculture practices for this commercially important species.

Feeding graded levels of protein to Genetically Improved Farmed Tilapia (GIFT) juveniles reared in inland saline water: Effects on growth and gene expression of IGF[sbnd]I, IGF-IR and IGF-BPI

To investigate the effect of dietary protein levels on growth performance,body composition,intestinal digestivenzyme activities of Cichlasoma sp. juvenile,fish meal and soybean mealwere chosen as the main dietary protein source,nd five diets containing protein content of 37%,40%,43%,46% and 49% were prepared and fed to Cichlasoma sp.uvenile for 6 weeks. Group of -5 fish with initial bodyweight of 0. 66 gwas fed in recycling aquarium (0. 8 m ×0. 5 m ×. 5 m,-00 L ofwater volume) with aerated water. Each group was trip licate. Fish were fed 4 times (8: 30,11: 30,14:0 and 17: 30) per daywith a feeding rate of 3% -4% of bodyweight. The temperature was (-7 ±1) ℃,and dissolvedxygen (DO) content was more than 5 mg/L during the growth study. The results showed that the weight gain (WG) ofhe five group s were 868. 51%,935. 95%,1018. -8%,9-5. 16%,873. 86%,and feed conversion rate (FCR ) were. 55%,1. 48%,1. 41%,1. 47% and 1. 56%,respectively. Fish fed with 43% dietary protein had the highestWG andowest FCR. The relationship of WG and dietary protein level could be expressed with regression equation: Y (weightain,% ) = 23.277-X2+281. 84X (dietary crude protein content,% ) 2 5076. 1 (R2= 0. 83-8). In the respect ofody composition,with the increase of dietary protein,the content of crude protein and ash of whole body increased,buthe crude fat decreased. Fish fed with diet of 49% protein content had significant higherwhole body crude protein and ashontent but lower whole body crude fat content than that fed with diet of 37% protein content. There was no significantifference in whole body moisture content among all group s. Protease activities of foregut’s tissue of the five group s were40. 80 U/g,718. 03 U/g,73-. -6 U/g,686. 1- U/g,596. 51 U/g,and protease activities of foregut’s chyme were-6. 26 U/g,948. 84 U/g,141-. 43 U/g,1304. 66 U/g and 1406. 93 U/g,respectively. Liver’s GPT and GOT activi-ies (Reitman-Frankel) were 69. 89 U/g,75. 75 U/g,89. 05 U/g,91. -0 U/g,90. 66 U/g,and 140. 63 U/g,163. 08/g,181. 80 U/g,150. 65 U/g,150. 80 U/g,respectively. Results above showed that Cichlasoma sp. juvenile had theest growth performance and the highest intestinal protease activities,the highest liver’s GOT and GPT activities,whenhey fed with diet of 43% dietary protein content,which showed that the op timal dietary protein requirement for Cichlaso-a sp. juvenile was 43%.  

Potential of feed pea ( Pisum sativum) meal as a protein source in practical diets for milkfish ( Chanos chanos Forsskal)

Six experimental diets (crude protein 12.58%, crude fat 1.93%, and total energy 10.72 kJ/kg) containing 0.24%, 0.37%, 0.51%, 0.62%, 0.77%, and 0.89% phosphorus were formulated to evaluate dietary phosphorus requirement for sea cucumber Apostichopus japonicus. The feeding trial was conducted in 18 fiberglass tanks (220 L) for 63 days. Each diet was randomly assigned to triplicate tanks of 50 sea cucumbers (9.99 g) and fed once daily. With the increase of dietary phosphorus level, weight gain (WG), specific growth rate (SGR), daily feed intake (DFI), feces production ratio, the activities of amylase, alkaline phosphatase, phosphofructokinase, succinate dehydrogenase, and glutathione peroxidase as well as the contents of glutathione and glutathione oxidized significantly increased and then decreased afterwards (P < 0.05). A. japonicus fed diet with 0.63%, 0.63%, and 0.55% dietary phosphorus was estimated to yield the highest WG (11.39 g), SGR (1.09%/d), and DFI (2.55%/d) according to the quadratic regression analysis of WG, SGR, and DFI against dietary phosphorus level, respectively. The apparent digestibility of dry material and energy followed an opposite tendency. Feed efficiency, the contents of whole-body phosphorus, initially increased and then plateaued, fitting piecewise-linear models with breakpoint at 0.57% and 0.55% dietary phosphorus. Daily phosphorus intake, pyruvate kinase activity, and the ratio of glutathione and glutathione oxidized increased (P < 0.05) but the apparent digestibility of phosphorus, the activities of alkaline protease, aspartate transaminase, and phosphoenolpyruvate carboxykinase decreased (P < 0.05), responding to the increasing dietary phosphorus. Considering the present results, the optimal dietary phosphorus for A. japonicus is 0.57–0.63%.

A 3 × 2 factorial experiment (protein levels, 42%, 46%, 50%; lipid levels, 9%, 12%) with three replicates was conducted in a circulating water system to investigate the effects of dietary protein and lipid levels on growth, feed utilization, body composition, and serum biochemical parameters of growing rockfish Sebastes schlegeli (initial weight, 29.98 ± 0.10 g). After an 8 weeks feeding trial, growth performance in terms of final body weight, percent weight gain, and specific growth rate increased with the increase of dietary protein level when fish fed diets containing a consistent level of dietary lipid. The feed conversion rate and daily feed intake were significantly affected by dietary protein and lipid levels, and decreased as dietary protein level increased from 42% to 46% or dietary lipid level increased from 9% to 12% (P < 0.05). Survival rate, viscerosomatic index, and hepatosomatic index were unaffected by dietary protein level (P > 0.05), but significantly increased with the increase of dietary lipid level (P < 0.05). On the contrary, condition factor was unaffected by dietary lipid level (P > 0.05), but significantly increased with dietary protein level increasing up to 46% (P < 0.05). The moisture contents of muscle and liver significantly decreased, but the whole-body crude lipid content, the crude protein and lipid contents of muscle increased as dietary protein or lipid level increased (P < 0.05). The contents of isoleucine, leucine, histidine, glycine, alanine of muscle, as well as the proportions of C14 : 0, C20 : 1, and C22 : 1n-9 in total fatty acids were higher in fish fed diets containing 12% lipid than those fed 9% lipid (P < 0.05), while C18 : 1n-9 and C18 : 2n-6 followed an opposite trend. The contents of phenylalanine, lysine, and tyrosine as well as the proportions of C18 : 0, C18 : 2n-6, C22 : 1n-9, and C22 : 6n-3 in total fatty acids decreased with the increase of dietary protein level (P < 0.05). Serum cholesterol and low-density lipoproteins increased significantly with dietary protein or lipid levels increasing, but TG concentration was elevated significantly in fish fed diets containing 12% lipid. Considering the present results in terms of growth and feed utilization, the suitable protein and lipid levels in diet for growing rockfish were 46% and 12%, respectively.

Effects of dietary protein levels on growth, feed utilization and expression of growth related genes of juvenile giant grouper (Epinephelus lanceolatus)

A six-week growth trial was conducted to evaluate the optimum dietary isoleucine requirement of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Seven isoenergetic (3,400 kcal/kg of dry matter), isoproteic (496 g/kg of dry matter) and isolipidic (70 g/kg of dry matter) diets were formulated to contain graded Ile levels (7.3, 11.3, 15.7, 19.6, 23.5, 26.8 and 30.8 g/kg, dry-matter basis). Each experimental diet was fed to triplicate groups of 12 hybrid grouper juveniles (average initial body weight: 6.00 ± 0.01 g/fish). Experimental fish were randomly distributed into 21 glass tanks (L 60 × W 45 × H 50 cm) connected to mechanical and biological water filters as a recycling system. Fish were fed twice daily (08:00 and 16:00) to apparent satiation. After the sampling of the growth trial, the remaining fish in each group were fed their corresponding diets for 2 d and then exposed to 4 mg Cu2+ · L−1 water for 24 hr. Results showed that growth performance and feed utilization were significantly affected by different dietary Ile levels (p < .05). Weight gain percentage (WG%), protein productive value (PPV), protein efficiency ratio (PER) and feed efficiency (FE) were increased as dietary Ile level increased, reaching a peak value at 19.6 g/kg dietary Ile, and thereafter, these four parameters declined as dietary Ile level continued to increase. Daily feed intake (DFI) showed an opposite tendency of variations as FE. The quadratic regression analysis of WG%, PPV, PER and FE against dietary Ile levels indicated that the optimum dietary Ile requirement for hybrid grouper was estimated to be 19.8, 20.8, 19.4 and 19.1 g/kg dry matter, respectively. Among all experimental treatments, fish fed 19.6 g/kg dietary Ile had the highest expression of growth and protein synthesis-related genes, including growth hormone (GH) in pituitary, insulin-like growth factor 1 (IGF-1), growth hormone receptor 1 (GHR1), target of rapamycin (TOR) and S6-kinase 1 (S6K1) in liver. Gut micromorphology was significantly influenced by dietary Ile levels. After the exposure to 4 mg Cu2+ · L−1 water for 24 hr, fish fed 19.6 g/kg dietary Ile had the highest survival and the best immunologic manifestation among all experimental treatments. Generally, the optimum dietary Ile requirement for maximum growth of hybrid grouper was estimated to be 19.8 g/kg dry matter, corresponding to 39.9 g/kg dietary protein.

Optimum dietary crude protein for culture of genetically improved farmed tilapia (GIFT), Oreochromis niloticus (Linnaeus, 1758) juveniles in low inland saline water: Effects on growth, metabolism and gene expression

The dourado, Salminus brasiliensis, presents excellent farming characteristics, such as fast growth and excellent flesh quality. However, the lack of the knowledge on the species nutritional requirements and biological value of feedstuffs hamper the formulation of diets for optimized performance and, consequently, the species' intensive farming. To determine de species nutritional requirements, juveniles dourado (5.29 0.21 g) were stocked in 75 cages (60-L) set up in 1,000-L containers, and fed for 60 days diets containing levels of crude protein (CP) between 35 to 51% (4% increments) and gross energy (GE) varying of 4,200 to 5,000 kcal/kg feed (200 kcal increments). The trial was set up in a completely randomized design, 5 5 factorial scheme (five levels of GE and five levels of CP, with three replications). Data on weight gain (WG), percentage weight gain (PWG), daily feed consumption (DFC), food conversion ratio (FCR), specific growth rate (SGR) and nutrient retention were recorded. No interaction (P>0.05) between dietary energy and protein levels for all parameters was detected. The values of DFC, WG, RWG, FCR, SGR and nutrient retention were affected (P<0.05) by the dietary protein and energy levels. DFC decreased with increasing energy levels. The liposomatic and viscerosomatic indexes were affected (P<0.05) by dietary energy levels, and increased with increasing energy levels. Through broken line analysis technique, the requirements estimated for optimum performance and nutrient and energy retention of dourado were 45.08% CP, 4,600.0 kcal GE/kg, and a energy:protein ratio varying between 10.20 and 10.65 kcal of GE/g of CP. Apparent digestibility is one of the main tools to evaluate the potential of an ingredient to be used in aquafeeds. To evaluate the apparent digestibility coefficient (ADC) of energy and nutrients of animal and plant protein sources in practical diets for the dourado (19.49 5.04 g), fish were stocked in plastic cages (80-L) and fed pelleted test diets containing 30% of test ingredients plus 70% of a reference diet (RR) containing 48.14% CP, 4,453.2 kcal GE/kg, and 0.1% of chromium oxide III. After the last daily meal, cages were transferred to cylindrical conical-bottomed aquaria (200-L) where feces were collected by sedimentation in refrigerated containers. ADCs of nutrients and energy of selected protein sources differed (P<0.01); ADC values were: 94.25; 91.26; 93.05 and 93.47% for CP, 91.03; 90.33; 87.83 and 88.78% for GE, 92.06; 84.49; 80.58 and 79.25% for ash, 83.90; 80.26; 84.25 and 84.55% for dry matter, 97.38; 96.74; 93.32 and 91.46% for lipid for fish meal (FM), poultry by-product meal (PBM), soybean meal (SBM), and corn gluten meal (CGM), respectively. The average ADC of amino acids was: 93.60; 89.95; 92.07 and 92.45% of FM, PBM, SBM and CGM, respectively. All tested ingredients were efficiently used and can partially replace FM in diets for carnivorous dourado.

Adaptabilities of fish to different kinds of food and nutrient composition show that fish digestive system has the ability to adapte to food, and corresponding to these alterations the activities of digestive enzymes of fish would change greatly. Sturgeon culture has been progressing in late decade years. Some researchers have investigated the nutrition requirements and feeding regimes for different sturgeon. But literature on the digestive enzymes in sturgeon is still few The objective of the present study was to determine protease, lipase and amylase activities in six different sturgeon species: A. schrencki, A. ruthenus, A. baeri, A. guldenstadti, Hybrid sturgeon( Huso huso L. ♀× A . ruthenus ♂)and A. Sinensis. Six species of sturgeon were reared with artificial diets special for sturgeon in the Centre of Sturgeon Breeding of Chinese Academy of Fishery Sciences. Fish of similar age were selected. They wave devided in to two size groups: fingerlings(5-15g)and goung (48-250g) except for bester which had lower weight (mean of 46g). After starvation for 24 h, fish were sampled randomly and killed for the enzyme activities assays. The fish were dissected on ice and the alimentary canal and liver cleaned, washed with chilly distilled water. The alimentary canal was cut as stomach and gut portions. The stomach, liver and intestine were then minced and homogenized separately with 20 volumes of cold 0.75% sodium chloride solution to one part by weight of the minced tissue. Each homogenized sample was then centrifuged at 3500r/min for 10 min and the supernatant collected and prepared for enzyme assay at 4℃. The supernatant need be diluted with five folds before determining the protease activities in stomach or intestine. Total proteolytic activity was measured using the casein hydrolysis method. Proteolytic enzyme activity was defined as the amount of enzyme needed to catalyze the formation of μg of tyrosine per 1 min using 1g of fresh tissue at 30℃ and under pH 7.6(pH 2.2 for stomach). Amylase activity was determined by the starch hydrolysis method(BSZU, 1978). Amylase activity was expressed as mg of starch hydrolyzed using 1g of fresh tissue per 30 min at 30℃ and under pH7.6. Lipase activity was estimated in accordance with the method described in BSZU (1978). Its activity was expressed as the amount of enzyme needed to hydrolyze the lipid in 1g of fresh tissue μg of fatty acid per min at 30℃and under pH7.6. All spectrometric analyses were carried out using a Shimadzu UV-visible spectrophotometer(UV-2401 PC). All samples were assayed in triplicate with 2-3 fry fish or 1-2 fingerling fish each. The results were expressed as mean±s.d. The activities of protease, lipase and amylase in digestive organs (stomach, intestine and liver) of six species of juvenile sturgeon were determined at two growth stages. Among the three digestive organs of the six species, protease activity in intestine was the highest, but lowest in liver. Protease activity in intestine was significantly higher than those in the other two tissues ( P P &amp;gt;0.05);Amylase activity in intestine was the highest, and significantly higher than that of stomach or liver( PP &amp;gt;0.05). Except for individual differences, the activities of the three kinds of digestive enzymes were roughly the same among the six species. The results show that the intestine of tested sturgeons is the main digestive spot in digestion of food, the stomach ranks the second. &amp;nbsp;

Dietary phenylalanine level could improve growth performance, glucose metabolism and insulin and mTOR signaling pathways of juvenile swimming crabs, Portunus trituberculatus

Seven isoenergetic semi-purified test diets containing graded levels of protein ranging from 20 to 50% were formulated using fish meal and casein as the protein sources. Test diets were fed to triplicate groups ofBarbodes caldwellijuveniles with initial body weights of 1.26±0.02 g for eight weeks. The results indicated no significant effect of dietary protein levels on survival rate, relative weight of the viscera and relative weight of the liver in the juvenile fish. The weight gain and specific growth rate of the fish were found to be greater as dietary protein levels increased from 20 to 35%, but were not affected significantly as dietary protein level increased from 35 to 50%. Feed efficiencies did not differ significantly when fish were fed diets with protein levels from 30 to 50%, but were significantly higher than those of fish fed diets with protein levels of 20 and 25%. The protein efficiency ratio (PER) was negatively correlated with diet protein level (x) (PER=3.006−0.03251x,R=0.9366). There was no significant effect of dietary protein levels on carcass moisture, crude protein and ash. However, carcass lipid levels (L) decreased with an increase in dietary protein level (x) (L=8.2169−0.0458x,R=0.8551). There was no significant variation in hepatopancreas protease activity among the tests. Intestine protease activity and hepatopancreas amylase activity were increased to some extent, and then decreased as dietary protein levels continued to rise. The intestine amylase activity (IAA) of the juveniles was negatively correlated with dietary protein level (x) (IAA=84.625−0.9147x,R=0.8463). It was estimated that the suitable protein level for theB. caldwellijuvenile is 34% (the broken-line model was used to regress the relationship of the weight gain of the juvenile and dietary protein level).

Dietary protein requirement of juvenile spotted knifejaw Oplegnathus punctatus