Journal of Animal Physiology and Animal Nutrition最新文献

We hypothesized that nitrogen (N) and phosphorus (P), as two pivotal nutrients that contributed to the growth of growing animals, may have interactive effect on growth performance and microbial development in young calves. For this purpose, feeding two starter protein contents (20% [20CP] vs. 24% [24CP], DM basis) and two phosphorus supplementation levels (0.35% [0.35P] and 0.70% [0.7P], DM basis) was evaluated on growth performance, health indicators, digestibility of nutrients and microbial protein synthesis (MPS), the latter estimated from urinary purine derivatives (PDs). Forty-eight female Holstein calves (3 days of age) were assigned randomly to the following treatments: 20CP-0.35P, 20CP-0.7P, 24CP-0.35P and 24CP-0.7P (n = 12, each). Milk feeding schedule was identical among treatments until weaning (d 59), but study lasted until d 73. Feeding 24CP compared to 20CP diet tended to improve starter intake, increased average daily gain (ADG) during pre-weaning period (p < 0.05), and final body weight (p = 0.01). Higher P supplementation has marginal effect on starter intake but improved ADG (pre-weaning; p = 0.02) and microbial activity by greater MPS (p = 0.02) compared to 0.35P. The greatest starter intake, the most favourable general appearance score, the highest withers height, the highest hip height, the greatest organic matter and neutral detergent digestibility, and the greatest MPS were found when calves fed diets contained 24CP along with 0.7P in starter. Based on the current study results, N and P have separate effects on the growth performance of young calves; however, their positive interaction can be attributable to growth performance and microbial development, especially during the pre-weaning period.

This study aimed to estimate metabolizable energy (ME), protein (MP) and amino acids (MAA) requirements for maintenance and growth, and to develop a mathematical model to predict ADG for beef cattle using a meta-regression approach. A data set including 91 sources of literature with 385 treatments was assembled after data collection and screening. To estimate nutrient requirements for maintenance and growth, metabolizable nutrient intakes were regressed on metabolic body weight (MBW) and ADG using a mixed model with a random study effect. A multiple linear regression model was derived to predict ADG using MBW and nutrient intakes as independent variables. The random forest analysis was used to identify the importance of independent variables associated with ADG and compare it with the multiple linear regression model. The accuracy of the model was evaluated by Monte−Carlo cross-evaluation. The ME and MP requirements for maintenance were 0.56 MJ/BW^0.75 and 4.31 g/BW^0.75. The maintenance requirements of metabolizable arginine (Arg), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), threonine (Thr), tryptophan (Trp), phenylalanine (Phe), valine (Val) and total AA were 0.044, 0.073, 0.013, 0.13, 0.10, 0.024, 0.075, 0.026, 0.088, 0.11 and 0.76 g/BW^0.75. The estimated ME and MP requirements for growth were 45.8 MJ/kg ADG and 398.7 g/kg ADG. The growth requirements of metabolizable Arg, His, Ile, Leu, Lys, Met, Thr, Trp, Phe, Val and total AA were 4.5, 6.4, 7.3, 24.0, 2.9, 2.4, 6.1, 1.7, 9.5, 9.3 and 74.5 g/kg ADG. The multiple linear regression analysis showed that ADG was positively correlated with intakes of ME, ether extract, starch and Trp (p < 0.05). The results of the Monte−Carlo cross-evaluation showed that the multiple regression model was more accurate in predicting ADG than the random forest model. ME and MP requirements for maintenance are consistent with previous studies, but requirements for growth tend to be overestimated. Future studies are needed to evaluate MAA requirements. An accurate model was developed to predict ADG, offering a theoretical basis and guidance to improve growth performance and feed conversion efficiency for beef cattle.

The present investigation explored the growth performance, haematological parameters and serum biochemistry of flathead grey mullet under recirculating aquaculture system (RAS) and traditional culture systems. Nine hundred healthy fish, weighing 43.80 ± 3.55 g and length 16.54 ± 0.82 cm were randomly distributed to three treatments of RAS and traditional culture systems (T₁: 20% of water changed daily; T₂: once-through system 250 L/h; T₃: RAS—20% of water changed weekly) in nine concrete tanks of 4000 L at stocking density of 100 fish/tank and each treatment had three replicates. Fish were fed (33.1% crude protein, 3 mm pellets) twice a day at a rate of 3% for 12 weeks. These findings suggest that the T₃ followed by T₂ led to notable improvements in growth performance compared to other culture systems. Significantly elevated values of weight gain, length gain, specific growth rate, average daily gain and survival % were observed in T₃. The RBCs exhibited a significant decrease under T₂. Haemoglobin concentrations and WBC counts significantly increased under RAS. Significant values of mean cell haemoglobin and mean cell haemoglobin concentration were recorded in T₂. Total protein, albumin and globulin enhanced significantly under RAS, whereas the highest values of cortisol were observed in T₂ and T₃. These findings demonstrate that the RAS followed by once-through system significantly improve growth performance, feed efficiency and survival, as well as enhancing the haematology and serum biochemical status of flathead grey mullet. In conclusion, RAS provides ideal conditions for optimizing physiological functions, growth performance and fish health.

The use of carbohydrates in animal feed is a way to save protein in the diet. This study evaluated the effect of protein/starch ratio on the performance, hepatic metabolism, and body composition of juvenile tambaqui (Colossoma macropomum). Six isoenergetic experimental diets were formulated containing three levels of digestible protein (P: 230, 260 and 290 g kg⁻¹) and two levels of starch (S: 180 and 280 g kg⁻¹): P23S18, P23S28, P26S18, P26S28, P29S18 and P29S28. Juveniles tambaqui (N = 288; initial weight = 30.0 ± 3.8 g) were fed experimental diets for 90 days and the zootechnical performance was evaluated. Nine fish from each treatment group were sampled to determine somatic indices, blood metabolites, tissue energy reserves, body composition and activity of key hepatic enzymes. Blood triglycerides, hepatosomatic index, liver and muscle lipids, and hepatic glycogen increased significantly with starch while blood glucose, triglycerides and cholesterol, muscle lipids were significantly impacted by protein levels. Fish-fed S28 had increased feed intake (1714–1829 g; p < 0.0001) and fish-fed diet P26S18 had a higher protein efficiency rate (23.62%; p = 0.0356). Fish fed P23 had lower crude protein retention in the carcass (p = 0.0018) and high lipogenesis and lipid deposition in the muscle (p = 0.0069). These results suggest that dietary carbohydrates have a protein-sparing effect. Tambaqui adapted well to diets containing starch, even at higher levels, resulting in an overall increase in lipogenesis from S18 to S28. Thus, we recommend P26S18 as a cost-effective feed that ensures both zootechnical performance and quality of the final product.

Antibiotics are used in swine production for growth promotion and disease prevention, raising concerns about environmental contamination and antibiotic resistance. In this study, we investigated the effects of enramycin supplementation on piglet growth, gut microbiota and blood metabolites. Enramycin promotes piglet growth and temporarily reduces diarrhoea. Gut microbiota analysis revealed changes in microbial composition, including an increase in the abundance of Limosilactobacillus reuteri. Metabolomic analysis has identified elevated levels of dimethylglycine, a known growth-promoting factor, in the enramycin group. Liver gene expression analysis revealed increased mRNA levels of ALDH and dimethylglycine dehydrogenase, which are enzymes involved in dimethylglycine metabolism. The enramycin-treated group had a higher concentration of acetic acid in caecal contents, and their caecal acetic acid concentrations were positively correlated with the abundance of L. reuteri and the content of serum dimethylglycine, respectively. These findings suggest that the promotion effect of enramycin on piglet growth is related to the gut microbiota, blood metabolites and liver gene expression, which provide insights into antibiotic alternatives for swine production.

Soybean agglutinin (SBA) is an anti-nutritional factor in soybean, possesses toxic effects by binding to intestinal epithelial cells, and finally interferes the digestion and absorption of nutrients in humans and animals. Annexin A2 (ANXA2) is one of the SBA-specific binding proteins in intestinal epithelial cells and participates in multiple cellular biological processes. However, whether SBA affects apoptosis through ANXA2 and its apoptosis-related pathway remains unclear. IPEC-J2 is an ideal model to study human intestinal health. Therefore, this study aims to investigate the effects of ANXA2 on SBA-induced intestinal epithelial cell apoptosis and the related pathway mechanism using IPEC-J2 as a cell model. The results showed that SBA induced the apoptosis through FAK signal pathway and decreased the gene and protein expressions of ANXA2 in IPEC-J2. The expression of ANXA2 protein had a negative correlation with the apoptosis rates, and a positive correlation with the expression of FAK protein and FAK pathway downstream proteins. In conclusion, SBA induced apoptosis of IPEC-J2 cells by downregulating the expression of ANXA2, which activated the FAK pathway. These findings highlight the toxic mechanism of SBA, which will provide basis for studying the toxicity mechanisms of other food-derived anti-nutrients and provide a new perspective for human gastrointestinal health and related cancer treatment.