Protein Deposition Rate Research Articles

Effects of High Dietary Starch Levels on the Growth Performance, Liver Function, and Metabolome of Largemouth Bass (Micropterus salmoides)

In this study, we conducted a 16-week feeding trial to investigate the effects of a high-cassava starch diet on growth performance, liver function, and metabolism in largemouth bass (Micropterus salmoides). We formulated five diets containing varying levels of cassava starch: 12%, 9%, 6%, 3%, and 0% (termed M12, M9, M6, M3, and M0, respectively). We distributed these diets among largemouth bass with the initial body weight of 83.33 ± 0.55 g via an in-pond “raceway” aquaculture system. Our findings suggest that high level (12%) of cassava starch dietary inclusion adversely affected growth performance metrics such as weight gain rate and specific growth rate, along with feed utilization efficiency indicators, including protein efficiency, protein deposition rate, and the apparent digestibility of dry matter and protein. This negative impact was accompanied by a decrease in intestinal amylase activity. Through further transcriptomic analysis, we identified several key genes associated with carbohydrate metabolism, which underwent changes influencing liver function. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed the involvement of these differentially expressed genes (DEGs) in the tricarboxylic acid cycle (TCA cycle). Comparative metabolomics analysis further indicated that the M9 group showed significant enrichment in pathways related to amino acid metabolism and alterations in the levels of metabolites involved in carbohydrate metabolism. In conclusion, our study demonstrates that incorporating up to 9% cassava starch in the diet can enhance growth performance in largemouth bass by stimulating digestive enzyme activities and promoting glucose utilization.

Inactivated lactobacillus plantarum promoted growth performance, intestine health and antioxidant capacity of juvenile largemouth bass, Micropterus salmoides

To evaluate the effects of inactivated Lactobacillus plantarum (LPM) on carnivorous fish, juvenile largemouth bass [initial body mass: (5.62±0.13) g] were fed five isonitrogenous and isoenergetic diets containing 0 (M0), 200 (M1), 400 (M2), 600 (M3), and 800 (M4) mg/kg LPM for 8 weeks. The results showed that in terms of growth, weight gain rate (WGR) and specific growth rate (SGR) showed significant second-order polynomial trend with increasing LPM supplementation. WGR and SGR of the M3 group were significantly increased by 14.18% and 5.62%, respectively, compared with the M0 group. Significant linear and second order polynomial trends were observed for feed conversion ratio (FCR), protein efficiency ratio (PER) and protein deposition rate (PDR) with the increase in dietary LPM. FCR was significantly reduced by 8.9% in the M2 group compared to the M0 group. In terms of intestinal health, intestinal amylase, intestinal villi number, length and width showed significant second order polynomial trends with increasing LPM supplementation. Significant linear and second order polynomial trends were observed for intestinal lipase activity, liver crude fat content with increasing dietary LPM. Dietary LPM supplementation of 600 mg/kg significantly increased the abundance of beneficial bacteria. In terms of antioxidant capacity, with the increase of LPM supplemental level, superoxide dismutase activity, malondialdehyde content of serum and liver, and liver Cu/Zn-SOD, Keap-1 and TGF-β1 mRNA expression levels showed significant linear and second-order polynomial trend, and Nrf2 mRNA expression level showed a significant second-order polynomial trend. Overall, the appropriate level of LPM (400–600 mg/kg) promoted the growth performance and feed utilization of largemouth bass by increasing the abundance of intestinal bacteria, improving the activities of digestive enzymes and antioxidant enzymes, and up-regulating the mRNA expressions of genes related to antioxidants.

Dietary Threonine Promoted the Growth and Ovarian Development of the Red Swamp Crayfish (Procambarus clarkii).

To explore the effects of dietary threonine on growth and ovarian development of red swamp crayfish (Procambarus clarkii), crayfish (5.48 ± 0.19 g) were fed six isoproteic and isoenergetic diets with varying levels of threonine (7.16 g/kg (control), 9.19, 12.74, 16.44, 20.83, and 23.78 g/kg) for 8 weeks. The results showed that weight gain rate, feed conversion ratio, protein efficiency rate, protein deposition rate, and essential amino acid deposition rates obtained the optimal values when the dietary threonine level was 12.74 or 16.44 g/kg. Compared to the control group, the 12.74 g/kg group exhibited enhanced nonspecific immunity and antioxidant properties. The 16.44 g/kg group demonstrated a significant increase in the frequency of B cells and R cells in the hepatopancreas, the length and width of intestinal villi, and the activities of protease and lipase. It also showed elevated ecdysterone hormone, gonadal index (GI), cAMP content, and the relative abundance of beneficial intestinal microflora. Compared to the control group, the mRNA expression of mTOR, S6K1, 4EBP1, EcR, RXR, chitinase, PKA, Vg, cdc2, and cyclin B was significantly upregulated, and the mRNA expression of MIH was significantly downregulated in the 16.44 g/kg group. Overall, optimal dietary threonine could improve intestinal health, regulate immune function, and enhance protein utilization, molting, and growth performance of red swamp crayfish. Additionally, it improved the synthesis of yolk substance and facilitated the development of ovarian cells of female crayfish. The optimal threonine level was 14.87-16.94 g/kg (dry matter), corresponding to 42.51-48.42 g/kg of dietary protein in red swamp crayfish.

28 Investigation of protein deposition pattern of PIC337×Camborough commercial pigs

Abstract The objective of the trial was to investigate the protein deposition pattern of PIC337×Camborough commercial pigs. A total of 1,064 barrows and gilts [PIC337×Camborough, initial body weight (BW) = 6.0 ± 0.1 kg] were used in the trial with 38 mixed sex pens, 28 pigs per pen. At the beginning of the trial, the lightest 10% of the barrows and gilts were selected and placed in four pens (equal numbers of barrows and gilts within a pen), and the remaining pigs were randomly placed into the other pens (equal numbers of barrows and gilts within a pen). A common 6-phase corn-soybean based wean-to-finish diets were fed throughout the trial. Dietary net energy and standardized ileal digestible lysine levels were (6-10 kg BW: 2,600 Kcal/kg and 1.35%; 10-20 kg BW: 2,520 Kcal/kg and 1.30%; 20-38 kg BW: 2,470 Kcal/kg and 1.20%; 38-72 kg BW: 2,450 Kcal/kg and 0.98%; 72-127 kg BW: 2,450 Kcal/kg and 0.87%; and 127-149 kg BW: 2,450 Kcal/kg and 0.77%). On d 97 after placement, 5 barrows and 5 gilts with BW close to pen average were selected for individual BW by a portable scale and 10th rib backfat and loin depth measurements (ExaGo portable ultrasound scanner, Imv imaging, UK). Then on d 111, 117, 136, 142, and 167 after placement, the same 5 barrows and 5 gilts were measured for individual BW, 10th rib backfat and loin depth. The fat-free lean mass is estimated by the equation 6.783-0.6198×(10th rib backfat depth, mm)+0.1578×(10th rib loin depth, mm)+1.0362×(warm carcass weight, kg). A constant carcass yield of 75% was used to estimate warm carcass weight. Data were analyzed using a linear mixed model in R Studio (Version 3.5.2, R Core Team; Vienna, Austria). The average BW of pigs at the 6 measurements were: 77.2, 92.4, 99.2, 122.5, 128.0, and 153.6 kg, respectively. The average daily gain (ADG) was 1,139, 1,155, 1,145, 1,126, and 977 g/d for 77.2 to 92.4 kg BW, 92.4 to 99.2 kg BW, 99.2 to 122.5 kg BW, 122.5 to 128.0 kg BW, and 128.0 to 153.6 kg BW, respectively. The average daily 10th rib backfat depth gain was 0.05, 0.08, 0.15, 0.17, and 0.20 mm/d. The average daily 10th rib loin depth gain was 0.42, 0.43, 0.41, 0.39, and 0.23 mm/d. The average daily fat-free lean mass gain (ADFFLG) was 547, 551, 528, 515, and 422 g/d. The fitted quadratic model for ADG is 83.57782 + 19.90632 × (BW, kg)-0.09176×(BW, kg)2, and the calculated maximum ADG was 1,163 g/d when BW was 108.5 kg. The fitted quadratic model for ADFFLG is 85.90926 + 9.23773 × (BW, kg) - 0.04591 × (BW, kg)2, and the calculated maximum ADFFLG is 550.6 g/d when BW was 100.6 kg. Under the conditions of the current trial, PIC337×Camborough pigs reaches the maximum rate of protein deposition at BW between 100.6 and 108.5 kg.

Estimation of in vivo body composition of Iberian pigs using bioelectric impedance and ultrasonography techniques

Iberian pigs are renowned for their high-quality products and distinctive characteristics, including high fat accumulation, low protein deposition rate, and a long productive cycle. The study aimed to assess in vivo body composition of purebred Iberian pigs using bioimpedance analysis (BIA) and ultrasonography. Accurate estimation of body composition in live animals is crucial for adopting decisions at the farm level. The experiment involved three groups of pure male Iberian pigs differing in body weight (BW; 60, 80 and 100 kg) with the same nutritional management. Body measurements, BIA and back fat and loin thickness (measured by ultrasonography) were obtained before slaughter. After slaughter pig carcasses were chemically analysed. A strong correlation between BIA measurements, specifically resistance (Rs) values, and body chemical parameters (total protein, lipids, ash, and water contents; p < 0.001 for all) was found. Reactance values (Xc), however, did not exhibit significant correlations. Regression analyses were conducted to predict carcass composition based on BIA measurements, BW, ultrasonography and linear corporal measurements. The prediction models achieved high R2 values for lipids, protein, total ash, water, and lean tissue (0.957, 0.968, 0.936, 0.961 and 0.976, respectively, p < 0.001 for all), indicating strong predictive power. These findings demonstrate the potential of non-invasive techniques such as BIA for estimating body chemical composition and quality of pig carcasses. However, it is important to acknowledge that the prediction models developed may not be applicable to other pig populations, as they were based on a specific sample of pigs.

Comparative study on the utilization of four forms exogenous methionine by red swamp crayfish (Procambarus clarkii)

To investigate the efficacy of four forms of methionine (Met) supplementation in red swamp crayfish (Procambarus clarkii), a Met-deficient all-plant protein diet was used control, along with four supplemental diets: 0.90 g/kg Met-Met, 1.80 g/kg crystal DL-Met, 3.60 g/kg E-Met, and 3.29 g/kg MHA-Ca. The analysis Met + Cys levels of five diets were 10.46 (control), 11.51, 12.50, 12.56, and 10.70 g/kg, respectively. Each diet was hand-fed to five replicates of 18 crayfish each (initial body weight: 4.40 ± 0.02 g) for eight weeks. Supplementation with four forms of exogenous Met resulted in an increase in weight gain rate, specific growth rate, and antioxidant capacity, while decreasing the feed conversion ratio (P < 0.05). The abdominal muscle crude protein content and the protein deposition rate in the Met-Met and E-Met groups were higher than those of the control group (P < 0.05). The deposition rate of Met, arginine, leucine, lysine, threonine, and valine, and the activities of digestive enzymes were higher in the Met-Met group than that of the control group (P < 0.05). The peak times and values of serum biochemical indices were affected by four forms of exogenous Met. Additionally, the hepatopancreatic homocysteine content in the MHA-Ca group was higher than in the control group (P < 0.05). In conclusion, the utilization of Met-Met by Procambarus clarkii was superior to other forms of Met in an all-plant protein diet.

Black soldier fly (Hermetia illucens) larvae meal improves quail growth performance.

The aim of the present study was to determine the nutritional value of black soldier fly (BSF) larvae meal for quail (experiment I) and the dose-response effects of BSF levels on growth performance, relative organ weight, and body composition of growing quails (experiment II). In experiment I, 100 35-day-old quail were distributed in a completely randomized design, with two treatments (reference and test diet) and 10 replicates. The experimental period consisted of 5days of adaptation, followed by 5days of total excreta collection. The experimental feed consisted of a reference diet and a test diet formulated with 850g/kg reference diet and 150g/kg BSF. In experiment II, 1000 1-day-old quail were distributed in a completely randomized design, with five dietary levels of BSF (0, 25, 50, 75, and 100g/kg). At 42days of age, birds were slaughtered, and the relative organ weight and body composition were determined. Apparent metabolizable energy values corrected for nitrogen retention of BSF meal were 13.8MJ/kg. Across the starter (1-14days) and overall period (1-42days), increasing BSF levels had a quadratic effect on body weight and body weight gain. Feed conversion ratio was quadratically affected during the starter phase and linearly reduced over the overall period. Additionally, the BSF levels linearly decreased the small intestine's relative weight at 42days and had a quadratic effect on the rate of protein deposition. We concluded that the inclusion of 100g/kg BSF meal improves feed conversion ratio for growing quail.

Dandelion Root Extract in Trout Feed and its Effects on the Physiological Performance of Oncorhynchus mykiss and Resistance to Lactococcus garvieae Infection

Abstract In this study, we investigated the dietary effects of dandelion root extract (DRE) on growth performance, body composition, serum biochemical parameters, intestinal and liver histology, and fish resistance against Lactococcus garvieae infection in the rainbow trout. In total, 540 rainbow trout fry (22.05±1.740 g and 13.03±0.470 cm) were used. Six experimental groups (control, 2.5 mL/kg (DRE-1), 5 mL/kg (DRE-2), 10 mL/kg (DRE-3), 20 mL/kg (DRE-4), and 40 mL/kg (DRE-5) dandelion root extract) with three replicates were formed. In each tank, 30 fish were placed and fed for 90 days, and the volume of water was adjusted to 80 L with a flow-through system. The results showed that the final fish weight, weight gain, specific growth rate, protein efficiency ratio, and protein deposition rate were significantly higher in the DRE-4 group, while the feed conversion ratio and fat deposition ratio were significantly lower compared to that in the control group (P&lt;0.05). The viscerosomatic index and the hepatosomatic index decreased in the experimental groups depending on the concentration of the extract used, while the condition factor was higher than that in the control (P&lt;0.05). The DRE significantly decreased glucose, cholesterol, triglyceride, low-density lipoprotein, alanine aminotransferase, and aspartate aminotransferase levels in blood serum in the fish from the experimental groups, but it significantly increased high-density lipoprotein, alkaline phosphatase, and total protein levels (P&lt;0.05). Similarly, the DRE positively affected intestinal histology by increasing the stratum compactum, submucosa, lamina propria, villi length, villi width, absorption area, tunica muscularis thickness, mucosal folds, and goblet cell count. In the liver, depending on the high-fat diet (crude lipid = 20%), vacuolization areas, hepatocellular degeneration areas, apoptotic hepatocyte nucleus, and necrotic areas recorded in the control group decreased or even disappeared completely in the extract groups. The results of the challenge test showed that adding 2.5 mL/kg of the DRE to the feed positively affected the disease resistance against Lactococcus garvieae infection. The results of the quadratic polynomial regression showed that an average level of 23.91±1.048 mL/kg of DRE would be suitable for optimum fish growth.

Growth, Feed Utilization, Lipid Metabolism, and Metamorphosis of Bullfrog (Aquarana catesbeianus) Tadpoles Fed Diets With Different Lipid Levels.

This study investigated the effect of dietary lipid levels on growth performance, lipid metabolism, antioxidant capacity, digestive enzyme activity, and metamorphosis rate of bullfrog (Aquarana catesbeianus) tadpoles. A total of six isonitrogenous diets were prepared, each containing 4.46% (L5), 6.95% (L7), 9.10% (L9), 10.90% (L11), 12.34% (L13), and 15.00% (L15) crude lipid content. The experimental diets were administered to triplicates of tadpoles (stage 25, 0.007 g) twice daily for 75 days with a daily feeding rate of 6.50% of their body weight. Weight gain (WG), specific growth rate (SGR), crude protein content of the whole body, apparent digestibility of dry matter and gross energy, intestinal lipase (LPS) capacity, lipoprotein lipase (LPL), and carnitine palmitoyltransferase-I (CPT-I) and contents of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in the liver, high-density lipoprotein cholesterol (HDL-C) content in the serum, and metamorphosis rate at stages 40 and 41 increased as the dietary lipid level increased from 4.46% to 12.34% and then decreased. As the dietary lipid level increased from 4.46% to 10.90%, the protein efficiency ratio (PER), protein deposition rate (PDR), lipid deposition rate (LDR), crude lipid content and gross energy of the whole body, apparent digestibility of the crude lipid, superoxide dismutase (SOD), catalase (CAT) activities in the liver, and the intestinal trypsin (TPS) activity all increased and then decreased. According to the second-order polynomial regression analysis of the WG and metamorphosis rate at stage 41 to the dietary lipid level, the ideal dietary lipid content for tadpoles was 11.08% and 10.72%, respectively. Overall, the appropriate dietary lipid level for bullfrog tadpoles was found to be 10.72%-11.08% of the diet.

Positive effects of dietary Clostridium butyricum supplementation on growth performance, antioxidant capacity, immunity and viability against hypoxic stress in largemouth bass.

The effects of dietary supplementation of Clostridium butyricum (CB) on growth performance, serum biochemistry, antioxidant activity, mRNA levels of immune-related genes and resistance to hypoxia stress were studied in largemouth bass. Feed with CB0 (control, 0 CFU/kg), CB1 (4.3×108 CFU/kg), CB2 (7.5×108 CFU/kg), CB3 (1.5×109 CFU/kg) and CB4 (3.2×109 CFU/kg) CB for 56 days, and then a 3h hypoxic stress experiment was performed. The results showed that dietary CB significantly increased the WGR (weight gain rate), SGR (specific growth rate), PDR (protein deposition rate) and ISI (Intestosomatic index) of largemouth bass (P<0.05). Hepatic GH (growth hormone)/IGF-1 (insulin-like growth factor-1) gene expression was significantly upregulated in the CB3 and CB4 groups compared with the CB0 group (P<0.05), while the FC (feed conversion) was significantly decreased (P<0.05). Serum TP (total protein) and GLU (glucose) levels were significantly higher in the CB4 group than in the CB0 group (P<0.05), while the contents of serum AST (aspartate transaminase), ALT (alanine transaminase), AKP (alkline phosphatase) and UN (urea nitrogen) in CB4 were significantly lower than those in CB0 (P<0.05). T-AOC (total antioxidant capacity), SOD (superoxide dismutase), CAT (catalase), POD (peroxidase) and GSH-Px (glutathione peroxidase) activities were significantly higher in CB3 and CB4 groups than in CB0 group (P<0. 05). The liver MDA (malondialdehyde) content of CB1, CB2, CB3 and CB4 groups was significantly higher than that of CB0 group (P<0. 05). The relative expressions of IL-1β (interleukin 1β), TNF-α (tumor necrosis factor α) and TLR22 (toll-like receptor-22) genes in CB2, CB3 and CB4 groups were significantly lower than those in CB0 group (P<0.05). The relative expression of IL-8 (malondialdehyde) and MyD88 (Myeloid differentiation factor 88) genes in the CB4 group was significantly lower than that in the CB0 group (P<0.05). The liver LZM (lysozyme) content of CB2, CB3 and CB4 groups was significantly higher than that of CB0 group (P<0. 05). The relative expression of IL-10 (interleukin 10) and TGF-β (transforming growth factor β) genes in the CB4 group was significantly higher than that in the CB0 group (P<0.05). Under hypoxic stress for 3h, the CMR of CB0 group was significantly higher than that of CB1, CB2, CB3 and CB4 groups (P<0.05). Dietary CB can improve the growth performance and resistance to hypoxic stress of largemouth bass by regulating the expression of GH/IGF-1 gene and inflammatory factors and inhibiting TLR22/MyD88 signaling pathway.

Net Portal Appearance of Amino Acids in Iberian and Landrace Pigs Fed Different Protein Content in the Diet

Iberian pigs have low rates of muscle protein deposition compared with modern breeds. Differences in net portal appearance (NPA) of amino acids (AA) might partially explain that. NPA of AA was measured in six Iberian and six Landrace gilts (28 kg) fitted with catheters in portal and mesenteric (para-aminohippuric acid infusion) veins, and carotid artery. Blood samples from porta and artery were simultaneously taken at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, and 6-h after feeding two isoenergetic diets (14-14.5 MJ metabolizable energy/kg dry matter) with different crude protein (145 (LCP) and 187 (HCP) g/kg dry matter) content. NPA of essential AA (EAA) and non-essential AA (NEAA) was lower (p < 0.05) in Iberian than Landrace pigs, and in LCP than HCP diet. Fractional absorption (NPA/AA intake) of EAA, NEAA, and total AA was, respectively, 36, 49, and 44% lower in LCP than HCP diet in Iberian pigs; and 8, 2, and 4% greater in Landrace pigs. Fractional absorption of EAA, NEAA, and total AA was 42, 68, and 60% lower in Iberian than Landrace pigs fed LPC diet; and 1, 36, and 26% when fed the HCP diet. NPA of AA may partially explain the low growth rate of Iberian pigs.

Effects of Dietary Steroid Saponins on Growth Performance, Serum and Liver Glucose, Lipid Metabolism and Immune Molecules of Hybrid Groupers (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatu) Fed High-Lipid Diets.

High-lipid diets are attributed to excessive lipid deposition and metabolic disturbances in fish. The aim of this experiment was to investigate the effects of steroidal saponins on growth performance, immune molecules and metabolism of glucose and lipids in hybrid groupers (initial weight 22.71 ± 0.12 g) fed high-lipid diets. steroidal saponins (0%, 0.1% and 0.2%) were added to the basal diet (crude lipid, 14%) to produce three experimental diets, designated S0, S0.1 and S0.2, respectively. After an 8-week feeding trial, no significant differences were found between the S0 and S0.1 groups in percent weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and protein deposition rate (p > 0.05). All those in the S0.2 group were significantly decreased (p < 0.05). Compared to the S0 group, fish in the S0.1 group had lower contents of serum triglyceride and low-density lipoprotein cholesterol and higher high-density lipoprotein cholesterol and glucose (p < 0.05). The activities of superoxide dismutase, catalase and glutathione peroxidase were significantly higher, and malondialdehyde contents were significantly lower in the S0.1 group than in the S0 group (p < 0.05). Hepatic triglyceride, total cholesterol and glycogen were significantly lower in the S0.1 group than in the S0 group (p < 0.05). Activities of lipoprotein lipase, total lipase, glucokinase and pyruvate kinase, and gene expression of lipoprotein lipase, triglyceride lipase and glucokinase, were significantly higher in the S0.1 group than in the S0 group. Interleukin-10 mRNA expression in the S0.1 group was significantly higher than that in the S0 group, while the expression of interleukin-6 and tumor necrosis factor-α genes were significantly lower than those in the S0 group. In summary, adding 0.1% steroidal saponins to a high-lipid diet not only promoted lipolysis in fish livers, but also activated glycolysis pathways, thus enhancing the utilization of the dietary energy of the groupers, as well as supporting the fish's nonspecial immune-defense mechanism.

Performance, metabolism, and meat quality of broilers fed dry brewery residue.

A study was conducted to assess the chemical composition and apparent metabolizable energy (AME), nitrogen-corrected AME (AMEn), and their respective coefficients of dry brewery residue (DBR) for broilers. A second study was conducted to evaluate the increasing inclusions of DBR in broiler diets and its effects on growth performance, carcass traits, blood metabolites, and meat quality. In the first trial (metabolism assay), a total of 250 male broilers were assigned to 5 diets (0, 100, 200, 300, and 400g DBR/kg) composed by 5 replications with 10 animals per cage in a completely randomized design in the period from days 11 to 21. There was an increasing linear effect for AME, AMEn, metabolizable coefficient of gross energy (MCGE), and MCGE corrected for N (MCGEn). In the second experiment, a total of 840 one-day-old male broiler chickens were assigned to 6 treatments (0, 20, 40, 60, 80, and 100g DBR/kg) with 7 replications and 20 animals per pen, from days 0 to 42. Growth performance was determined at days 21 and 42. There was an increasing linear effect for weight gain in the period from days 0 to 21 and for feed intake from days 0 to 42. A linear decreasing effect was observed at day 21 for cholesterol and quadratic effect for uric acid (UA), aspartate aminotransferase, and albumin. At day 42, there was a quadratic effect for UA and creatinine. At day 21, an increasing linear effect was observed for protein deposition rate. In conclusion, the inclusion of DBR up to 100g/kg improved WG in the starter phase and did not negatively affect the productive parameters of broilers from days 0 to 42.

Feeding juvenile largemouth bass (Micropterus salmoides) with carboxymethyl cellulose with different viscous: Impacts on nutrient digestibility, growth, and hepatic and gut morphology

A 56-day trial investigated the impact of the dietary inclusion of cellulose with different viscosities on the growth, nutrient digestibility, serum biochemical indices, and the hepatic and gut morphology of largemouth bass juveniles. Four practical diets (42.50% protein and 13.70% lipid) were designed containing 8% microcrystalline cellulose (MC) and carboxymethyl cellulose (CMC) of 2,500, 5,000, and 6,500 mPa s dynamic viscosity [named MC, low-viscosity CMC (Lvs-CMC), medium-viscosity CMC (Mvs-CMC), and high-viscosity CMC (Hvs-CMC) groups, respectively]. Fish of a uniform size (6.0 g) were randomly assigned into 16 cages, with 40 fish per cage. The results showed that the protein and lipid deposition rates, specific growth rate, protein efficiency ratio, and the weight gain rate decreased significantly in the CMC groups compared to the MC group, whereas the feed intake and feed coefficient rate exhibited the opposite trend. Moreover, the intestinal Na+/K+-ATPase, alkaline phosphatase, and lipase activities significantly decreased in the Mvs-CMC and Hvs-CMC groups compared to the MC group, as well as the serum triglyceride, total cholesterol, and high-/low-density lipoprotein contents. The nutrient apparent digestibility significantly decreased in the CMC groups compared to the MC group. The viscerosomatic and intestinal length indices in the CMC groups and the villus height in the Hvs-CMC group were significantly lower than those in the MC group, whereas the number of gut goblet cells and muscular thickness in the Mvs-CMC and Hvs-CMC groups exhibited opposing results. The results also showed that dietary CMC damaged the hepatic and gut morphology and decreased the digestive enzyme activity, nutrient apparent digestibility, and growth of largemouth bass. In summary, viscosity is the main anti-nutritional effect of dietary CMC and soluble non-starch polysaccharides.

High dietary non-starch polysaccharides detrimental to nutrient digestibility, digestive enzyme activity, growth performance, and intestinal morphology in largemouth bass, Micropterus salmoides.

An 8-weeks feeding trial was carried out to evaluate the effects of different levels of dietary non-starch polysaccharide on the growth, apparent nutrient digestibility, intestinal development, and morphology of largemouth bass (Micropterus salmoides). Seven isoproteic and isolipidic experimental diets were formulated (crude protein 47.00%, crude lipid 12.50%), containing 0, 3, 6, 9, 12, 15, and 18% non-starch polysaccharides (NSPs) (named Control, NSPs3, NSPs6, NSPs9, NSPs12, NSPs15, and NSPs18), respectively. Dietary inclusion of NSPs below 9% showed no negative impacts on fish growth and feed utilization efficiency, whereas dietary NSPs inclusion level above 9% decreased weight gain rate, specific growth rate, protein efficiency, protein deposition rate, apparent digestibility of dry matter and protein, and were accompanied by a reduction in intestinal protease, Na+/K+-ATPase and alkaline phosphatase activity and an increase in feed intake and feed coefficient. The activity of lipase was significantly decreased when dietary inclusion of 15 and 18% NSPs. Moreover, the lipid deposition rate and the apparent digestibility of lipids were significantly decreased since dietary inclusion of 9% NSPs. Dietary inclusion of NSPs above 12% significantly up-regulated intestinal GLP-2 gene's expression, and was accompanied by significant changes in hindgut morphology, including increases in villus length and width, muscularis thickness and number of goblet cell, as well as a decrease in crypt depth. Additionally, dietary inclusion of NSPs above 3% significantly increased intestinal length index, and the viserosomatic index was significantly increased when dietary NSPs exceeded 15%. The linear regression analysis based on weight gain rate and feed coefficient showed that the appropriate dietary NSPs level of juvenile largemouth bass should not above 5.51%. In conclusion, high dietary NSPs adversely affects digestive enzyme activity and intestinal morphology, which in turn reduced the apparent digestibility of dietary nutrients and growth of juvenile largemouth bass.

Study of enzyme-hydrolyzed soybean replacing fish meal and/or chicken meal on the growth of channel catfish (Ictalurus punctatus)

This study aimed to evaluate the effect of enzyme-hydrolyzed soybean (EHSB) to replace fish meal and chicken meal in channel catfish (Ictalurus punctatus) on the growth performance, serum biochemical indices and gastrointestinal structure of channel catfish. The channel catfish (initial weight: 21.25 ± 0.25 g) was fed four isonitrogenous, isolipidic and isophosphorous diets for 60 days. The control diet (CON group) contained 8% fish meal and 5% chicken meal. EHSB was used to replace fish meal (100%, RF group), chicken meal (100%, RC group), and 100% of fish meal and chicken meal (RFC group), respectively. The specific growth rate (SGR) and protein deposition rate (PR) of channel catfish in RF, RC and RFC groups were significantly increased compared to the control group and reached their peaks in RFC group (SGR: 2.92%, PR: 45.64%) (P < 0.05). The feed coefficient of channel catfish in RFC group (0.94) was significantly decreased compared to the control group (P < 0.05). The survival rate was not affected by the replacement of fish meal and chicken meal by EHSB (P > 0.05). The catalase and alanine aminotransferase activities in serum were significantly decreased in replacement groups compared to the control group (P < 0.05). Besides, the activities of superoxide dismutase and aspartate aminotransferase in serum of channel catfish were remarkably increased in the RFC group (24.22 U/L and 193.00 U/L, respectively) (P < 0.05). The replacement of fish meal and chicken meal by EHSB, either alone or simultaneously, significantly increased the crude protein (51.68% in RC group) and crude lipid (31.27% in RFC group) in whole body of channel catfish (P < 0.05). The crude lipid in muscle of channel catfish was markedly increased in RF (16.31%, dry matter) and RFC groups (16.45%, dry matter) (P < 0.05). Replacement of fish meal and chicken meal by EHSB could significantly increase the intestinal villi length and intestinal wall thickness, thus improving the digestive capacity of channel catfish. The gastric epithelial cells in the RFC group were plumper and more structurally integrated than in the control group. In summary, replacing 100% of fish meal and 100% of chicken meal with EHSB could effectively improve the growth performance, antioxidation and digestive capacities of channel catfish.

Intestinal flora and immunity response to different viscous diets in juvenile largemouth bass, Micropterus salmoides

An 8-weeks feeding trial was conducted to estimate the effects of different viscous cellulose on the intestinal flora and health in juvenile largemouth bass (Micropterus salmoides). Four isoproteic and isolipidic experimental diets were formulated (crude protein 42.50%, crude lipid 13.70%) to contain 8% cellulose (control group; 5.14 mPa s), 8% low viscous carboxymethyl cellulose (CMC) with 800 mPa s (Lvs-CMC group; 182.15 mPa s), 8% middle viscous CMC with 2000 mPa s (Mvs-CMC group; 320.48 mPa s) and 8% high viscous CMC with 5000 mPa s (Hvs-CMC group; 440.65 mPa s), respectively. The weight gain rate, specific growth rate, protein efficiency ratio, protein and lipid deposition rate in the CMC groups were dramatically lower than those in the control group, while feed conversion rate showed an opposite result. Plasma diamine oxidase activity, endothelin-1 and lipopolysaccharide concentrations in the Mvs-CMC and Hvs-CMC groups were significantly higher than in the control group, accompanied by a significant down-regulation of Occludin, Caludin-1 and Caludin-4. Intestinal glutathione concentration, superoxide dismutase and catalase activities in the CMC groups were significantly lower than in the control group, accompanied by a significant up-regulation of Keap1 and down-regulation of Nrf2. Moreover, CMC diets dramatically down-regulated the expression levels of IL-10 and TGF-β1. Digesta total short chain fatty acid and acetate concentrations in the CMC groups were dramatically higher than in the control group, while butyrate concentration showed an opposite result. The OTU, Sobs, Shannon and Simpson indices of intestinal flora in the CMC groups were dramatically lower than in the control group. Notably, structural analysis showed that dietary CMC dramatically increased the abundance of C. somerae and P. shigelloides, but reduced the abundance of C. colicanis and C. perfringens. In summary, increasing dietary viscosity adversely affects the intestinal flora structure and diversity, increases acetate/butyrate-producing bacterial ratio and the abundance of pathogenic microorganisms, disrupting intestinal flora homeostasis, impairs mucosa barrier function, induces intestinal inflammation and epithelial cell apoptosis in juvenile largemouth bass. Our findings demonstrate that soluble cellulose is more detrimental to intestinal health and growth in juvenile largemouth bass compared to insoluble cellulose, and the adverse effects of soluble cellulose are mainly caused by its viscosity. Importantly, this study demonstrate that viscosity is the main characteristic of non-starch polysaccharides that are detrimental to the intestinal health of fish.

The interactive effect of dietary inclusion levels and preparation methods of myo-inositol on growth performance, antioxidant function and lipid metabolism homeostasis of Cyprinus carpio var. jian

To evaluate the interactive effect of inclusion levels (IL) and preparation methods (PM) of myo-inositol (MI) on growth performance, hepatic antioxidant capacity and lipid metabolism of Cyprinus carpio var. jian, five isonitrogenous and isoenergetic diets were formulated at a high level of dietary fat content (11.3%, HF basic diet), supplemented with 400 mg/kg or 800 mg/kg of enzyme biocatalysis MI (E-MI) (400E-MI, 800E-MI) and chemical acid hydrolysis MI (C-MI) (400 C-MI, 800 C-MI). 300 healthy C. Carpio var. jian (1.5 ± 0.1 g) were randomly fed one of the five experimental diets in triplicates (20 fish per tank) for 66 days. After the 66 days feeding trial, the growth performance, plasma biochemistry, hepatic antioxidant enzyme activities, and gene expressions related to lipid metabolism were determined. Two-way ANOVA analysis showed that PM and IL of dietary MI had an interactive effect on growth performance, antioxidant capacity and lipid metabolism of C. Carpio var. jian. The IL significantly affected protein deposition rate (PDR), activities of hepatic CAT, T-SOD and GPx (P < 0.05). Specifically, final average weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and PDR in the 400E-MI group and 800 C-MI group were significantly higher than those in the 400 C-MI group (P < 0.05). The oil red O staining results showed that a large amount of lipid accumulation in the liver tissues of the HF group, while the hepatic lipid accumulations of 400 C-MI, 400E-MI and 800 E-MI were significantly reduced (P < 0.05). The expressions of lipid metabolization-related genes showed that the myo-inositol PM and IL had an interactive effect on mRNA expressions of hepatic ACO, ACSL, PPARβ and SIRT1 (P < 0.05). The mRNA expression levels of ACC, AMPK, PPARβ and SREBP-1 were significantly affected by IL (P < 0.05). Specifically, The mRNA expressions of LPL, PPARβ and SIRT1 of 400 C-MI, 400E-MI and 800 E-MI groups were significantly higher than those of the HF basic group. Overall, the supplementation of C-MI and E-MI in the HF diet improved the protein deposition and liver antioxidant ability, promoted lipid metabolism through activating AMPK and SIRT1 of C. Carpio var. jian fed HF diet.

Validation of a mechanistic dynamic pre-weaned lamb growth and body composition simulation model

Lamb growth and body composition simulation models can provide valuable insights into the assessment of feeding regimens and rearing systems, allowing optimisation of farm profitability without the need for in-vivo trials. The objective of the present study was to evaluate the performance of a published mechanistic dynamic model on the growth and body composition of pre-weaned lambs using independently published data sets. Data generated from eight treatments, representing three artificial lamb rearing experiments (n = 77 lambs) were used. Initial body composition data were obtained from four lambs at approximately two days of age, with the remaining lambs being provided with defined nutritional treatments until the trial end-point. The body composition of lambs at slaughter was determined in six treatments across two experiments. Feed intake and live weight (LW) of lambs were recorded in all treatments. The LW, average daily gain (ADG) and ash deposition rates of lambs were accurately simulated by the model (paired t-test, P > 0.05). The overall empty body weight (EBW), gutfill, protein and fat deposition rates were overestimated, and water deposition rate was underestimated by the model (paired t-test, P < 0.05). Collectively, these results suggest that the model can be used at the farm level with acceptable accuracy to determine lamb growth. Further improvements in the model are required for protein, fat and water deposition rates, gutfill and EBW to make it more applicable for wider usage.

Effects of dietary arginine levels on intestinal morphology, digestive enzyme activity, antioxidant capacity and intestinal flora of hybrid snakehead(Channa maculata ♀×Channa argus ♂)

The effects of arginine on intestinal shape, digestive enzyme activity, antioxidant capacity, and intestinal flora of hybrid snakeheads Channa maculata♀×Channa argus♂. Five experimental diets were formulated to contain arginine with 2.31%, 2.42%, 2.72%, 2.92%, and 3.12% respectively, and recorded as G1 (control), G2, G3, G4, and G5. Five groups of 50 fish (22.02 ± 0.02 g) for each diet were fed to apparent satiation twice daily for 56 days. The results showed that significantly higher weight gain (WG), specific growth rate (SGR), protein deposition rate (PDR), intestinal somatic indices (ISI), lipase, trypsin, Na+/K+-ATPase, γ-glutamyl transpeptidase, and significantly lower feed coefficient rate (FCR) were observed in fish fed with 2.92% diet compared to 2.31% group (P < 0.05). There was a significant increase of intestinal villus length, villus width and muscular thickness in fish fed with 2.92% and 3.12% arginine diets compared with those in 2.31% group (P < 0.05). The fish fed with 2.92% or 3.12% arginine diets had significantly higher intestinal total antioxidant capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione peroxidase (GSH-Px) and lower malondialdehyde (MDA) compared to those in 2.31% group (P < 0.05). High-throughput sequencing revealed arginine supplementation can significantly increase the generation of probiotic bacteria and altered the composition of intestinal microbes. There was a significant increase of the abundance of Firmicutes and Proteobacteria in fish fed 3.12% arginine diets compared with those in 2.31% group (P < 0.05). Based on the WGR, a broken-line regression analysis showed that the appropriate level of arginine in the diet of hybrid snakehead was 2.95% (6.65% of the feed protein).