Whole-body Proximate Composition Research Articles

Effect of dietary chitosan on the growth performance, intestinal histology and growth-related gene expression in stellate sturgeon (Acipenser stellatus) juveniles.

As sturgeon breeding has proliferated, there has been a heightened demand for growth stimulators in their diets. This study aimed to determine the impact of dietary chitosan on growth performance, whole-body proximate composition, growth-related gene expression, and intestinal histology in juvenile Acipenser stellatus. A total of 180 A. stellatus juveniles with an average weight of 31.90 ± 0.73 g were fed with diets containing 0 (control), 1.5, 3.0, 4.5, and 6.0 g chitosan.kg-1 basic diet for eight weeks. The findings revealed a significant enhancement in growth performance with rising chitosan concentrations. Furthermore, chitosan supplementation upregulated the expression of the growth hormone gene in both brain and liver tissues. In liver samples, the most pronounced expression of the insulin-like growth factor-1 gene was noted at 6.0 g chitosan.kg-1, while in brain samples, peak expressions were observed in both the 4.5 and 6.0 g chitosan.kg-1 treatments. While the whole-body proximate composition remained relatively stable, there was a notable decrease in whole-body lipids with the escalation of chitosan dosage. Intestinal villi dimensions, both height and width, were amplified in the chitosan-supplemented groups compared to controls. In summation, chitosan supplementation showed promise in bolstering growth performance, refining intestinal morphology, and enhancing growth-related gene expression. Analysis of the polynomial regression of weight gain and specific growth rate revealed that the optimum dietary chitosan requirements in A. stellatus were 5.32 and 5.21 g chitosan.kg-1, respectively.

Effects of Tannic Acid Supplementation of a High-Carbohydrate Diet on the Growth, Serum Biochemical Parameters, Antioxidant Capacity, Digestive Enzyme Activity, and Liver and Intestinal Health of Largemouth Bass, Micropterus salmoides.

We investigated the effects of dietary tannic acid (TA) supplementation of a high-carbohydrate diet on growth, feed utilization, whole-body proximate composition, serum biochemical indicators, antioxidant capacity, digestive enzyme activity, and liver and intestinal health of juvenile largemouth bass, Micropterus salmoides (initial mean weight: 8.08 ± 0.08 g). Five diets were prepared, including a positive control (dietary carbohydrate level, 16%, LC0), a negative control (dietary carbohydrate level, 21%, HC0), and three TA-supplementation diets based on the negative control diet with TA addition at 200, 400, and 800 mg/kg, respectively. After 8 weeks of feeding, the results showed that compared with the LC0 diet, 400-800 mg/kg dietary TA significantly improved the survival rate of largemouth bass (P < 0.05) while significantly reducing its weight-gain rate and specific growth rate (P < 0.05). Compared with the HC0 diet, 400 mg/kg dietary TA significantly increased serum catalase activity (P < 0.05), and significantly decreased serum malondialdehyde, liver glycogen, lightness (L ∗), and yellowness (b ∗) (P < 0.05). Moreover, compared with the HC0 diet, 200-400 mg/kg dietary TA effectively improved the vacuolation of hepatocytes caused by the high-carbohydrate diet and reduced the occurrence of intestinal epithelial cell vacuolation and necrosis. In turn, 800 mg/kg dietary TA significantly inhibited protease activity in the pyloric caecum and intestine (P < 0.05). In conclusion, dietary supplementation with TA inhibited protease activity, which resulted in decreased growth performance in largemouth bass. However, it was also found that 200-400 mg/kg TA enhanced the antioxidant capacity of largemouth bass in the case of the high-carbohydrate diet, reduced liver glycogen levels, and improved liver and intestinal health. Finally, it should be noted that, when the dietary TA level exceeded 800 mg/kg, TA appeared to play a pro-oxidation role in the liver, which may cause oxidative stress in the liver.

Effects of dietary manganese supplementation on the growth performance, tissue manganese content and antioxidant capacity of coho salmon (Oncorhynchus kisutch) post-smolts

A 10-week growth trial was carried out to study the impact of dietary manganese (Mn) level on growth, tissue Mn content and anti-oxidative capacity of coho salmon (Oncorhynchus kisutch) post-smolts (186.51 ± 1.43 g). Six iso-nitrogenous (42.40% Protein) and iso-lipidic (10.27% Lipid) purified diets based on casein-gelatin were formulated to contain varied graded (MnSO4·H2O as a Mn source) levels of 0.40, 9.50, 16.80, 25.80, 33.40 and 41.20 Mn mg/kg. Fish were reared in a freshwater flow-through rearing system and fed to apparent satiation 3 times daily. No significant effects were found on the survival rate, morphological indices, whole-body proximate composition (p > .05) among the groups. However, higher dietary Mn supplementation level than 25.80 mg/kg improved the growth performance, increased the deposition of Mn in whole-body and vertebral, improved hepatic digestive enzyme activity, enhanced anti-oxidative enzyme activities, and decreased the malondialdehyde content in liver and serum (p < .05). Hepatic and serum total antioxidant capacity, glutathione peroxidase, glutathione reductase, total superoxide dismutase, Mn-superoxide dismutase and catalase activities were enhanced with increasing level of dietary Mn, and then stabilized when dietary Mn level up to 25.80 mg/kg. Using the cubic analysis (based on specific growth rate and feed conversion ratio), the optimal dietary Mn levels were 33.25 and 29.55 mg/kg, respectively. Using the broken-line analysis (based on the deposition of Mn, Mn-superoxide dismutase in liver and serum), the dietary Mn requirements of coho salmon post-smolts were estimated to be 24.52, 26.34, 24.74 and 26.05 mg/kg, respectively.

Response of growth performance, antioxidant capacity, and gut microbiota to dietary cholesterol and lecithin in the juvenile Redclaw crayfish, Cherax quadricarinatus

Dietary cholesterol and lecithin are two essential nutrients for the growth and health of crustaceans. A 56-day feeding trial was carried out to evaluate the effects of dietary cholesterol and lecithin on the growth performance, antioxidant capacity, intestinal digestive enzymes, and gut microbiota of the Redclaw crayfish, Cherax quadricarinatus. The crayfish (initial average weight 11.39 ± 0.28 g) were fed with six experimental diets formulated with different contents of cholesterol (0.5% and 1%) and lecithin (1%, 2%, and 3%). No additional cholesterol (0%) and lecithin (0%) were added to the diet of the control group. Crayfish fed the diet with 0.5% cholesterol and 2% lecithin improved growth performance, antioxidant capacity, and intestinal digestive enzyme activities than crayfish fed with other diets. Survival, condition factor, hepatosomatic index, and whole-body proximate composition of crayfish were not significantly affected by different dietary cholesterol and lecithin levels. The Proteobacteria, Firmicutes, and Actinobacteria dominate the gut microbiota community of C. quadricarinatus. In diets with 0.5% cholesterol and 2% lecithin, there were more positive connections and a more complex network structure, which may reduce the risk of pathogen infection. Overall, the combination of 0.5% cholesterol and 2% lecithin in C. quadricarinatus diets was optimal.

Comparative Study of Whole-Body Proximate Composition, Dressing Losses and Bioaccumulation of Heavy Metals in Muscle Tissues of Wild and Farm-Raised Labeo Rohita

The muscle tissues of wild and farm-raised rohu were analyzed for proximate composition (Crude protein, crude fat, ash, and dry matter) and uptake of heavy metals (Cd, Ni, Pb, and Cr) using the standard protocols. For this purpose, wild fish samples were collected from the Khanpur Canal, Sheikhupura, and farmed fish samples from a local fish market in Lahore. The results showed that the concentration (%) of protein (17.92±0.36), ash (06.54±0.13), and moisture (76.50±1.53), was observed to be higher in the wild when compared to protein (16.90±0.34), ash (5.07±0.10) and moisture (73.50±1.47) of farm-raised rohu. In contrast, crude fat contents were observed to be higher (4.02±0.08) in farm-raised rohu than wild (03.65±0.07). In terms of dressing losses, wild fish showed higher (26.37%) losses as compared to farm raised (25.83%). Results showed that in wild and farm fish’s muscles, the trend of the heavy metals was Pb &gt; Cd &gt; Ni &gt; Cr. The findings demonstrated that in comparison to Cd, Ni, and Cr, Pb concentration (ppb) was greater in both wild (128.32.82) and farm-raised (111.42.16) rohu. When compared to wild rohu, farmed rohu showed a higher bioaccumulation tendency for Cr and Ni, but Cd and Pb showed the reverse pattern. The findings of this study suggest that fish proximate composition, dressing losses, and bioaccumulation of heavy metals are certainly impacted by the aquatic life of freshwater fish like Labeo rohita both in wild and farmed conditions and these results will be helpful for the aquaculturists as well as the local consumers of the fish.

Graded levels of dietary pink oyster mushroom, Pleurotus djamor meal, affect growth, feed efficiency, lipase activity, and fiber content in final whole body of fingerlings of the Nile tilapia, Oreochromis niloticus (Actinopterygii: Cichliformes: Cichlidae)

The presently reported study was aimed to determine the effects of graded levels of dietary pink oyster mushroom (Pleurotus djamor) meal (POMM), in growth, feed efficiency, protein utilization, digestive enzymes activities, and whole-body proximate composition of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), fingerlings (0.3 ± 0.01 g). The experimental design included a control diet (POMM0) formulated with soybean meal, as the main protein source, and four diets designed with increasing levels of POMM: 25% (POMM25); 50% (POMM50); 75% (POMM75); and 100% (POMM100). Experimental diets were administered to 420 fish, randomly distributed in 15, 100-L tanks. The feeding experiment lasted 45 days. Diets and the final whole body were submitted to a proximate composition analysis. Growth, feed efficiency, protein utilization, and digestive enzyme activities were assessed. Compared to POMM0 and POMM25, weight gain (WG), and specific growth rate (SGR), significantly (P &amp;lt; 0.05) decreased in fish that were fed POMM50, POMM75, and POMM100%. Feed conversion ratio (FCR), protein efficiency ratio (PER), and survival rate (SR) were not significantly affected by experimental diets. Daily feed intake (DFI), and daily protein intake (DPI), decreased as POMM increased in diets. Compared to POMM0 experimental group, condition factor (K), showed a significantly higher value in fish that were fed POMM50, and POMM100 experimental diets. Crude fiber of the final whole body of POMM100 resulted in significantly higher (P &amp;lt; 0.05) compared to that shown in fish fed the rest of the experimental diets. Acid and alkaline proteases, trypsin, chymotrypsin, leucine aminopeptidase, and amylase of Nile tilapia fingerlings, were not significantly affected by experimental diets. Compared to fish fed POMM0 and POMM25 diets, experimental fish fed POMM50, POMM75, and POMM100 showed a reduction in lipase activity. In conclusion, a POMM level higher than 25% affects growth and lipase activity. While a POMM level higher than 50% affects fiber content in a whole body of the final fish.

Substituting dietary fishmeal with silkworm pupae meal in diets of Pacific white shrimp (Penaeus vannamei): Effects on growth performance, nutrient utilisation, whole-body composition and digestive enzyme activities

The present study evaluated the dietary substitution effect of silkworm pupae meal (SWP) forfish meal (FM) on growth performance, feed utilisation, whole-body proximate composition,amino acid profile and digestive enzyme activities of Pacific white shrimp (Penaeusvannamei). The shrimp were fed with six isonitrogenous (36% crude protein), isolipidic (8%crude lipid) and isocaloric (16 MJ kg-1) experimental diets, containing 0, 20, 40, 60, 80 and100% SWP, respectively, to replace dietary FM. A total of 360 shrimps (average initial weightof 3.86±0.20 g) were distributed into 18 tanks (20 shrimp per tank). The experimental dietswere fed to triplicate groups of P. vannamei three times a day until satiation for 45 days.Significantly (p&lt;0.05) higher growth performance and feed utilisation were found in shrimpfed diet with 60% incorporation level of SWP meal. No significant differences (p&gt;0.05) wereobserved in the survival rate, whole-body proximate composition and amino acid profile ofshrimp fed SWP meal-incorporated diets. Additionally, higher specific activities of digestiveenzymes such as amylase, trypsin and lipase were observed in shrimps fed diet with 60%incorporation level of SWP meal. The present study revealed that dietary fish meal proteinup to 60% can be substituted with SWP without compromising growth performance, feedutilisation, whole-body proximate composition, amino acid profile and digestive enzymeactivities of Pacific white shrimp fed on SWP meal based diets. Keywords:Amylase, Feed ingredient, Waste utilisation,Weight gain

Effects of two phosphorous sources in the diet on the growth performance, digestibility, and plasma physiological parameters of Pelodiscus sinensis juveniles

Phosphorus is an essential mineral for aquatic animals to maintain the health of the skeletal system and many physiological functions. This study assessed the effects of two inorganic phosphorus sources on growth performance, apparent phosphorus digestibility, whole-body proximate composition, and physiological status in juvenile Pelodiscus sinensis. Two experimental diets were supplemented with 4% calcium phosphate monobasic (MCP) and 5.47% calcium phosphate dibasic (DCP), respectively, to obtain equal total dietary phosphorus (2.20%). 96 turtles (initial body weight: 5.40±0.03g) were randomly distributed into 12 tanks and fed the corresponding diets for 60d. Results showed that phosphorus sources have not significantly influenced the growth parameters, including the specific growth rate, feeding rate, and feed conversion ratio (P&gt;0.05). No significant differences were observed in the hepatosomatic index and whole-body proximate compositions between MCP and DCP groups (P&gt;0.05). The apparent digestibility coefficients of dry matter and phosphorus in MCP group (53.22%) are slightly higher than that in DCP group (48.98%) but did not reach the statistically significant level (P &gt; 0.05). Turtles in MCP and DCP groups are the same in plasma physiological parameters and have equal alkaline phosphatase activities in plasma and liver (P&gt;0.05). In conclusion, calcium phosphate monobasic and calcium phosphate dibasic had the same biological phosphorus availability in diet for juvenile Pelodiscus sinensis.

FicoEst – a tool to estimate the body composition of farmed fish

ficoEst – Fish Composition Estimator is a public web tool to estimate the whole-body proximate composition of farmed fish (https://webtools.sparos.pt/ficoest/). The tool was designed for researchers in fish nutrition and fish farmers, and is available for six commercially relevant species: gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), meagre (Argyrosomus regius), rainbow trout (Onchorhynchus mykiss), Atlantic salmon (Salmo salar), and Nile tilapia (Oreochromis niloticus). ficoEst uses three different types of mathematical models (BC1, BC2, and BC3) to estimate the body composition of fish in terms of crude protein, crude lipids, water, ash, phosphorus, and energy. The models differ in the input data used to perform the estimates. BC1 models consider only body weight, BC2 models consider both body weight and water, and BC3 models consider body weight, water, and ash as inputs. The model evaluation results demonstrate that considering water and ash as additional inputs to body weight (BC3 models) significantly improves the accuracy in predicting some body composition components, such as crude lipids (e.g., up to 67.9 % and 28.1 % more accurate, compared to BC1 and BC2 models, respectively, depending on the species considered). ficoEst can be used as a complementary tool to analytical methods to obtain additional information about fish body composition. As a public web tool, ficoEst has the potential to be a valuable resource for researchers and fish farmers interested in estimating the body composition of farmed fish.

Effect of Four Functional Feed Additives on Growth, Serum Biochemistry, Antioxidant Capacity, Gene Expressions, Histomorphology, Digestive Enzyme Activities and Disease Resistance in Juvenile Olive Flounder, Paralichthys olivaceus.

An 8-week feeding trial was executed to evaluate the efficacy of four functional feed additives in replacing antibiotics in juvenile olive flounder, Paralichthys olivaceus, fed with a low-fish-meal diet. A basal diet without feed additives was used as a control (CON); other diets were formulated by supplementing 0.50% taurine (TW), 0.30% peptide (PT), 0.23% mineral water (MW), 0.35% yeast-extracted nucleotides (GRO), 0.35% GRO + 0.50% taurine (GROTW), 0.35% GRO + 0.30% peptide (GROPT) and 0.35% GRO + 0.23% mineral water (GROMW) into the basal diet; in addition, one diet was supplemented with oxytetracycline (OTC) at 0.5% as a positive control. Triplicate groups of 25 fish with an average weight of 5.15 ± 0.06 g (mean ± SD) were fed one of the nine experimental diets. At the end of the feeding trial, the weight gain, specific growth rate and protein efficiency ratio of fish fed the GRO, GROMW, GROPT and GROTW diets were significantly higher than those of fish fed the CON diet (p < 0.05). The feed efficiency of fish fed the GRO, GROMW, GROPT and GROTW diets was significantly higher than that of fish fed the TW and OTC diets. However, the survival, hepatosomatic index, viscerosomatic index and condition factor of fish, as well as their whole-body proximate composition, were not significantly affected by the experimental diets (p > 0.05). The serum glutamic pyruvic transaminase of fish fed the GROPT diet was significantly lower than that of fish fed the CON diet. However, glutamic oxaloacetic transaminase, glucose and total protein were not significantly affected by the experimental diets (p > 0.05). The serum superoxide dismutase activity of fish fed the PT, TW, GRO, GROMW, GROPT and GROTW diets was significantly higher than that of fish fed the CON diet. The lysozyme activity of fish fed the PT, GRO, GROMW, GROPT and GROTW diets was significantly higher than that of fish fed the CON and OTC diets. The myeloperoxidase activity of fish fed the TW, GRO, GROMW, GROPT and GROTW diets was significantly higher than that of fish fed the CON, PT and MW diets (p < 0.05). The flounder growth hormone gene expression of fish fed the TW, GRO, GROMW, GROPT, GROTW and OTC diets was significantly higher than that of fish fed the CON, PT and MW diets (p < 0.05). The interleukin 1β and interleukin 10 gene expressions of fish fed the GRO, GROMW, GROPT and GROTW diets were significantly higher than those of fish fed the CON, PT, TW and MW diets (p < 0.05). Intestinal histology showed a significantly higher villi length for fish fed the GRO, GROMW, GROPT and GROTW diets compared to that of fish fed the CON diet (p < 0.05). Digestive enzyme activities such as trypsin activity were significantly higher in fish fed the GROMW, GROPT and GROTW diets than those in the rest of the diet groups (p < 0.05). Amylase activity in fish fed the MW, GRO, GROMW, GROPT, GROTW and OTC diets was significantly higher than that of fish fed the PT, TW and CON diets (p < 0.05). On the other hand, the lipase activity of fish fed the TW, GRO, GROMW, GROPT and GROTW diets was significantly higher than that of fish fed the CON, PT, MW and OTC diets (p < 0.05). The cumulative survival rate of fish fed the PT, GROTW, GROPT and GROMW diets was significantly higher than that of fish fed the CON, TW and MW diets after thirteen days of the challenge testing. Overall, the results demonstrate that the GRO, GROMW, GROPT and GROTW diets could be beneficial feed additives to replace antibiotics in juvenile olive flounder fed low-fish-meal diets.

Dietary glutamine enhances growth performance and gut integrity of Totoaba macdonaldi juveniles fed low fishmeal diets but has limited synergetic effects in combination with a prebiotic

Fishmeal (FM) replacement using cost-effective blends of complementary ingredients is commonly used in carnivorous marine fish diets for economic and sustainable purposes. The use of functional compounds such as prebiotics or functional ingredients is a nutritional strategy in low FM diets to maximize growth and feed utilization, as well as reducing enteropathies caused by plant proteins, in particular soybean meal (SBM) that can induce enteritis in Totoaba macdonaldi juveniles. Therefore, this study was conducted to evaluate the effects of glutamine (Gln) and agavin (AGA) as a novel prebiotic or a combination of both on growth parameters, digestive capacity, whole-body proximate composition, gut health, and sustainable and economic indexes in totoaba juvenile fed low FM (17%) diet for 56 days. Juvenile totoaba with an initial weight of 168 ± 4 g were fed one of four isoproteic and isolipidic diets formulated with poultry by-product meal and FM in a 2:1 ratio and 24% of SBM. For the control basal diet (SBM), no Gln or AGA was added. The other three experimental diets consisted of the basal diet with either 1.5% glutamine (GLN), 1% prebiotic agavin (AGA), or 1.5% glutamine and 1% agavin (Gln + AGA) supplementation. Fish fed the Gln diet significantly improved growth, feed utilization and increased trypsin, total alkaline proteases, and L-aminopeptidase activities. Additionally, an enhanced brush border height (BBH) in the distal intestine was observed in the Gln group, suggesting improved intestinal health compared to the rest of the treatments. However, no significant synergistic effect was observed in fed fish the Gln + AGA diet. Interestingly, no signs of enteritis among the fish fed the four experimental diets was observed. These results suggest that fish with an initial size of 168 g are less susceptible to the adverse effects of SBM compared to previous studies. The inclusion of 1.5% dietary glutamine is recommended in totoaba diets with low FM containing 24% of SBM. Since the fish fed the diet supplemented with glutamine + agavin resulted in intermediate values for the parameters evaluated, it is recommended to evaluate different levels of agavin in combination with glutamine or perform longer bioassays using immunological or environmental challenges to aid in elucidating potential benefits of these functional compounds and their synergistic effects.

The effect of defatted black soldier fly meal (Hermetia illucens) inclusion in the formulated diet on the growth, gene expression, and histopathology of juvenile lobster (Panulirus ornatus Fabricius, 1798)

The present study investigated the potential use of defatted black soldier fly (Hermetia illucens) meal as a protein source in the formulated feed for juvenile lobsters, Panulirus ornatus. A total of 160 heads of juvenile lobsters with initial weight of 0.24 ± 0.01 g and initial length of 21.77 ± 0.32 mm were distributed evenly into 16 rectangular fiberglass aquaria and kept individually for 8 weeks of the feeding experiment. Four formulated feeds containing defatted BSF meal as fishmeal replacements at 0%, 25%, 35%, and 50% and total dietary protein to energy ratio of ~ 26 g CP MJ−1 were prepared and assigned as BSF0, BSF25, BSF35, and BSF50, respectively. Fishmeal is technically a suitable aquafeed ingredient in terms of crude protein, moisture, and amino acid compositions. The partially substituted defatted BSF meal has higher crude lipid and ash content than fishmeal. At the end of week 8 of feeding trial, the specific growth rate, length increment, survival rate, and moulting rate of juvenile lobster were not significantly (P > 0.05) affected by the fishmeal replacement. The fishmeal replacement with the defatted BSF meal did not significantly (P > 0.05) alter the whole-body proximate composition of the juvenile lobster. However, it significantly (P < 0.05) affected the superoxidase dismutase of juvenile lobsters. The cytokine cell expression analysis indicated that up to 35% of fishmeal replacement increased the inflammatory cytokine cells (Interleukin 8 and 17) of juvenile lobster, while an adverse impact was observed on juvenile lobster receiving 50% of fishmeal replacement by BSF meal. Histopathological analysis showed that the hepatopancreas cells of juvenile lobsters were damaged following fishmeal replacement beyond 35%. The present study indicated that up to 35% of defatted BSF meal can be used as fishmeal replacement in the formulated feed of juvenile lobster.

Evaluation of Yeast Hydrolysate in a Low-Fishmeal Diet for Whiteleg Shrimp (Litopenaeus vannamei).

An eight-week feeding trial was performed to evaluate the effects of yeast hydrolysate (YH) supplementation in a low-fishmeal diet on the growth, immune responses, intestinal histology and disease resistance of whiteleg shrimp (Litopenaeus vannamei). Five experimental diets were produced by supplementing YH at 0 (CON), 0.5 (YH0.5), 1 (YH1), 2 (YH2) and 4 (YH4) % to a basal diet containing 10% fishmeal and compared with a positive control with 25% fishmeal (FM25). Shrimp with an initial average weight of 0.43 ± 0.005 g (mean ± SD) were stocked in 18 tanks and fed the experimental diets (38% protein and 8% lipid) four times a day. Results showed that shrimp fed the FM25 diet exhibited significantly higher final body weight, weight gain, specific growth rate and protein efficiency ratio than those fed CON, YH0.5, YH1 and YH2 diets (p < 0.05). However, there were no significant differences between shrimp fed the YH4 and FM25 diets (p > 0.05). In addition, there were no significant differences in whole-body proximate composition, hemolymph biochemical parameters and non-specific immune responses among treatments. Intestinal villi length and muscular layer thickness of shrimp fed the YH4 and FM25 diets were significantly higher than the other groups. At the end of the bacterial (Vibrio parahaemolyticus) challenge test, shrimp fed YH4 and FM25 diets showed a significantly higher survival rate than those of shrimp fed CON, YH0.5 and YH1 (p < 0.05). These results suggest that supplementing 4% YH in diet containing 10% fishmeal could beneficially influence growth, intestinal morphology and disease resistance of whiteleg shrimp.

Dietary Riboflavin Requirement of Pacific White Shrimp (Litopenaeus vannamei).

This study was conducted to determine the dietary riboflavin requirement and its effects on growth performance, feed utilization, innate immunity, and diet digestibility of Litopenaeus vannamei. A riboflavin-free basal diet (R0) was formulated as a control, and six other diets were prepared by adding riboflavin of 10, 20, 30, 40, 50, and 60 mg/kg to the basal diet (designated as R10, R20, R30, R40, R50, and R60, respectively). Quadruplicate groups of shrimp (initial average weight 0.17 ± 0.00 g) were fed the diets six times a day for 8 weeks. Weight gain, specific growth rate, and protein efficiency ratio were significantly increased by riboflavin (p < 0.05). The maximum values were observed in shrimp fed R40 diet. The highest activities of phenoloxidase, nitro blue tetrazolium, superoxide dismutase, and glutathione peroxidase were observed in shrimp fed R40 diet. Lysozyme activity was significantly higher in shrimp fed R30 and R40 diets than that of shrimp fed R60 diet (p < 0.05). Intestinal villi were significantly longer in shrimp fed R50 and R60 diets compared to those of all other groups while the shortest villi were observed in R0 group (p < 0.05). Intestinal villi were clearly distinguished in shrimp fed higher levels of riboflavin compared to those of shrimp fed R0 and R10 diets. Apparent digestibility coefficients of dry matter and protein in diets were not significantly affected by riboflavin levels (p < 0.05). Whole-body proximate composition and hemolymph biochemical parameters were not significantly altered by dietary riboflavin (p < 0.05). Therefore, the results of this study indicate that riboflavin is essential to enhance growth performance, feed utilization, nonspecific immunity, and intestine morphology of shrimp. An optimal riboflavin requirement for the maximum growth of L. vannamei seems to be approximately 40.9 mg/kg diet.

Evaluation of growth, nutrient digestibility, and hematological parameters of tilapia, Oreochromis niloticus, fed diets containing different levels of high protein distiller's dried grain with yeast in it as replacement for corn protein concentrate

Two novel technologically advanced high protein distiller dried grains with yeast in it (HP50Y & HP40Y) were evaluated for juvenile tilapia. This experiment assessed the nutritional potential of using high protein (40 and 50%) distillers dried grain to replace corn protein concentrate (CPC) in formulation of tilapia diets for more sustainable development of aquaculture. A 10-weeks growth trial was conducted, using nine diets formulated to contain 32% protein and 6% lipid. Each protein was included at levels (0, 5, 10, 15 and 20%) replacing CPC on protein basis. Juvenile tilapia (mean initial weight 5.23 ± 0.20 g) were evenly distributed in thirty-six, 75-L aquaria working as a recirculating system and fed twice daily to apparent satiation throughout the study. Tilapia exhibited no significant (p > 0.05) differences in growth, FCR, survival, whole-body proximate composition, mineral composition, and hematological parameters when fed HP50Y and HP40Y supplemented diets compared to the control diet. Digestibility coefficients for the test ingredients were determined in tilapia for dry matter, energy, crude protein, individual and total amino acids using 1% titanium oxide as the inert marker with 70:30 replacement strategies. All the values were found in acceptable range for the distiller grains when compared to literature. Results from this study revealed that HP50Y and HP40Y both are good alternative protein sources and can be used up to 20% inclusion level in the diets of tilapia.

Poly-β-hydroxybutyrate has limited effects on growth and immune responses of juvenile hybrid striped bass Morone chrysops × M. saxatilis, and red drum Sciaenops ocellatus based on in vivo and in vitro approaches

Disease outbreaks in intensive aquaculture, particularly from bacterial pathogens, represent major constraints to efficient fish production. Therefore, development of novel disease treatment and prevention strategies have been receiving considerable attention in recent years. This study analyzed the efficacy of the organic acid poly-β-hydroxybutyrate (PHB) as an immunomodulator in hybrid striped bass (Morone chrysops × M. saxatilis) (HSB) and red drum (Sciaenops ocellatus) based on both in vitro and in vivo approaches. In vitro immunological assays, namely intra- and extra-cellular superoxide anion production and bactericidal capacity of HSB head kidney-derived leukocytes were determined to be significantly (P < 0.05) reduced when graded doses of sodium 3-hydroxybutyrate (3HB; 0.0, 0.5, 1.0, 2.0, 4.0 and 8.0 mM), a precursor to PHB, was supplemented in the cell culture media. For the HSB in vivo feeding trial, PHB-synthesizing bacteria, Zobellella denitrificans (ZD1), were supplemented to basal diets to produce five isonitrogenous and isolipidic experimental diets (40% crude protein and 10% crude lipid) containing PHB in stepwise increments (0.0, 0.125, 0.25, 0.5, 1.0, and 2.0% of dry-diet weight). In addition, a control diet was supplemented with 0.5% of a commercial purified PHB product. In a separate feeding trial, a commercial PHB product was supplemented to a practical basal diet in stepwise increments (0.0,0.125, 0.25, 0.5, and 1.0%) to isonitrogenous and isolipidic experimental diets (40% crude protein and 10% crude lipid). Juvenile HSB, and red drum (∼5.5, and 4.4 g/fish initial weight, respectively) in separate feeding trials were stocked in 38-L aquaria operated as a recirculating aquaculture systemHSB experimental diets were randomly assigned to quadruplicate aquaria of fish while the red drum experimental tdiets were randomly assigned to quintuplicate aquaria and fed for an 8-week period. HSB and red drum exhibited limited responses to graded levels of PHB, including percentage weight gain, feed efficiency, protein conversion efficiency and hepatosomatic index. Only juvenile red drum showed significantly (P < 0.05) increased muscle yield values with increasing dietary PHB while whole-body proximate composition analyses revealed no significant (P > 0.05) differences, except for HSB whole-body crude lipid. Thus, PHB (ZD1-derived and commercial) had limited effects on growth parameters, body condition factors, and immunological responses of both HSB and red drum juveniles.

Assessment of Safety, Effects, and Muscle-Specific Accumulation of Dietary Butylated Hydroxytoluene (BHT) in Paralichthys olivaceus.

Butylated hydroxytoluene (BHT) is a commonly used antioxidant added to animal/fish feed to limit lipid autoxidation and peroxidation. Although there have been reviews and reports of BHT toxicity in animals, limited information is available with respect to the toxic effects and accumulation of BHT due to oral exposure in aquaculture species. Therefore, 120 days of feeding trial was conducted to evaluate the effects of dietary BHT on the marine fish olive flounder Paralichthys olivaceus. Graded levels of BHT were added to the basal diet in increments of 0, 10, 20, 40, 80, and 160 mg BHT/kg, corresponding to 0 (BHT0), 11 (BHT11), 19 (BHT19), 35 (BHT35), 85 (BHT85), and 121 (BHT121) mg BHT/kg diets, respectively. Fish with an average weight of 77.5 ± 0.3 g (mean ± SD) were fed one of the six experimental diets in triplicate groups. Growth performance, feed utilization, and survival rate were not significantly affected by the dietary BHT levels among all experimental groups, whereas BHT concentration in the muscle tissue was found to increase in a dose-dependent manner up to 60 days of the experimental period. Thereafter, BHT accumulation in muscle tissue showed a declining trend among all treatment groups. Furthermore, the whole-body proximate composition, nonspecific immune responses, and hematological parameters (except triglycerides) were not significantly influenced by the dietary levels of BHT. Blood triglyceride content was significantly higher in fish fed the BHT-free diet compared to all other treatment groups. Thus, this study demonstrates that dietary BHT (up to 121 mg/kg) is a safe and effective antioxidant without exhibiting any adverse effects on the growth performance, body composition, and immune responses in the marine fish olive flounder, P. olivaceus.

Dietary Lactoferrin Supplementation Improves Growth Performance and Intestinal Health of Juvenile Orange-Spotted Groupers (Epinephelus coioides).

A 56-day feeding trial was conducted to investigate the effects of dietary lactoferrin (LF) supplementation on the growth performance and intestinal health of juvenile orange-spotted groupers fed high-soybean-meal (SBM) diets. The control diet (FM) and high-soybean-meal diet (SBM60) were prepared to contain 480 g/kg protein and 110 g/kg fat. Three inclusion levels of 2, 6, and 10 g/kg LF were added into the SBM60 to prepare three diets (recorded as LF2, LF6, and LF10, respectively). The results showed that the supplementation of LF in SBM60 increased the growth rate in a dose-dependent manner. However, the feed utilization, hepatosomatic index, whole-body proximate composition, and the abundance and diversity of intestinal microbiota did not vary across the dietary treatments (p > 0.05). After the dietary intervention with LF, the contents of the intestinal malondialdehyde, endotoxin, and d-lactic acid, as well as the plasma low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and total cholesterol were lower, and the intestinal activities of the glutathione peroxidase, lipase, trypsin, and protease were higher in the LF2-LF10 groups than that in the SBM60 group (p < 0.05). The supplementation of LF in SBM60 increased the muscle layer thickness of the middle and distal intestine and the mucosal fold length of the middle intestine vs. the SBM60 diet (p < 0.05). Furthermore, the supplementation of LF in SBM60 resulted in an up-regulation of the mRNA levels for the IL-10 and TGF-β1 genes and a down-regulation of the mRNA levels of the IL-1β, IL-12, IL-8, and TNF-α genes vs. the SBM60 diet (p < 0.05). The above results showed that a dietary LF intervention improves the growth and alleviates soybean meal-induced enteritis in juvenile orange-spotted groupers. The dietary appropriate level of LF was at 5.8 g/kg, through the regression analysis of the percent weight gain against the dietary LF inclusion levels.

Effect of Agricultural By-Products as a Carbon Source in a Biofloc-Based System on Growth Performance, Digestive Enzyme Activities, Hepatopancreas Histology, and Gut Bacterial Load of Litopenaeus vannamei Post Larvae

The present study evaluated the influence of different commercial agricultural by-products as a carbon source in a bifloc-based (BFT) culture system on growth performance, whole-body proximate composition, digestive enzyme activities, gut microbial abundance, and hepatopancreas histology of Pacific whiteleg shrimp, Litopenaeus vannamei post larvae (Pls). Three groups were designed, the first group was the control group, where the shrimp was reared in clear water (without carbon source addition and water exchange rate of 100% two times a week) and fed with a commercial diet, in the second and third groups shrimp were reared in BFT systems using two different carbon sources, sugarcane bagasse (SB) and rice bran (RB) without additional feeding or water exchange. The initial stocking density was 16 Pls/liter with an average individual shrimp weight of 0.01 ± 0.002 g and age (PL20). The experiment lasted 90 days. The water quality parameters were maintained at optimum levels during the experiment. The final body weight and specific growth rate of shrimp were significantly (p ≤ 0.01) higher in the control group than those reared in both SB and RB-based BFT. Meanwhile, the survival rate was significantly (p &lt; 0.05) higher in BFT groups than in the control. The protease activity in shrimp stomach did not differ significantly. Meanwhile, protease, lipase, and amylase in the intestine showed a significant increase (p &lt; 0.01) in BFT groups than those obtained in the control group. The total heterotrophic bacteria were significantly (p &lt; 0.05) higher in BFT groups. Furthermore, the hepatopancreas histological status of shrimp reared in the SB-based BFT group showed an increase in the hepatopancreas tubules in the distal and B-cell zones (blister-like cells) by 16.83 and 34.89%, respectively, compared to the control. This study revealed that BFT could be used as a natural feed without artificial diets, which influenced the gut microbiota of shrimp, increased digestive enzyme activities, as well as improved the histological structure of the hepatopancreas of shrimp. However, the success of this conditions under high stocking density still needs more investigation.

The Effects of Dietary Cottonseed Oil on Growth Performance of Juvenile Red Drum (Sciaenops ocellatus L.) and Hybrid Striped Bass (Morone chrysops × M. saxatilis S.)

Various cottonseed products containing higher levels of protein and lipid than traditional cottonseed meal have been evaluated in recent years with several carnivorous marine fish species. In previous studies in this laboratory, distinct differences in the acceptability of diets containing those cottonseed products were noted for red drum and hybrid striped bass. Therefore, the present study consisted of two concurrent feeding trials in which the effects of increasing levels of dietary cottonseed oil were evaluated with both juvenile red drum and hybrid striped bass. Three experimental diets were formulated to contain either 0, 2, or 4% of cottonseed oil in place of menhaden fish oil. All diets were formulated to contain approximately 9% lipid, with that of the basal diet (0% cottonseed lipid) primarily contributed by menhaden fishmeal and menhaden oil. In concurrent trials, each diet was fed twice a day to triplicate groups of juvenile red drum and hybrid striped bass initially averaging 1.86 g/fish and 1.41 g/fish, respectively, for 6 weeks. Results of the feeding trial showed that there were no significant differences among red drum fed the different dietary treatments based on growth parameters (weight gain and feed efficiency) or whole-body proximate composition. On the contrary, hybrid striped bass showed significant ( P ≤ 0.05 ) differences in responses to the dietary treatments with weight gain decreasing as the inclusion levels of cottonseed oil increased while their hepatosomatic index significantly increased. Thus, results of this study showed distinctly different responses of red drum and hybrid striped bass to increasing levels of dietary cottonseed oil, with hybrid striped bass being much more sensitive than red drum in terms of reduced weight gain and altered body condition which appeared to be related to reduce diet palatability from cottonseed oil.