Animal Nutrition最新文献

Low-protein (LP) diets are increasingly recognized as a cost-effective and efficient strategy in the global livestock industry. Although previous studies have demonstrated that increased valine intake during pregnancy can improve reproductive performance and mammary gland development in gilts, the effect of the standardized ileal digestible valine-to-lysine ratio (Val/Lys) in LP diets during lactation is not well understood. A total of 60 lactating sows (Landrace × Large White; 4th parity) were randomized by backfat and weighed into 6 groups (n = 10): a standard protein group (17% crude protein, Val/Lys of 0.87) and 5 LP diet groups (14.3% crude protein, Val/Lys of 0.64, 0.74, 0.84, 0.94 or 1.04). The experiment lasted from day 0 of lactation to day 21 of lactation. The results indicated that LP diets reduced (P < 0.05) weaning weight and average daily gain (ADG) in piglets, as well as sow milk yield; whereas, increasing Val/Lys in LP diets improved (P < 0.05) these parameters. A linear model determined an optimal Val/Lys ratio of 0.94 in LP diets for maximizing piglet ADG. Low-protein diets decreased jejunal trypsin levels in piglets, which increased (P < 0.05) when Val/Lys was increased. Furthermore, LP diets reduced the expression of transporters (solute carrier family 38 member 2, SLC38A2) and metabolic enzymes (branched-chain amino acid transaminase 1 and 2, BCAT1 and BCAT2) in the piglet jejunum; conversely, increasing Val/Lys enhanced these expressions. Levels of L-valine, DL-arginine and L-threonine were found to decrease (P < 0.05) in response to LP diets, as revealed by the results from sow serum metabolites. However, these concentrations rebounded (P < 0.05) when Val/Lys was increased to 0.94. Correlation analysis revealed a positive association between sow serum valine metabolites and jejunal expression of SLC38A2, BCAT1 and BCAT2 in piglets. Low-protein diets also led to a decrease in the protein levels of metabolic enzymes (P < 0.05), which were improved (P < 0.05) by increasing Val/Lys. Finally, correlation analysis revealed a positive correlation between sow serum metabolites, jejunal enzyme expression and piglet growth performance. Collectively, growth performance in piglets may be impaired by LP diets for sows due to valine transport and catabolism being disrupted, whereas growth performance may be enhanced by increasing Val/Lys in LP diets via sow milk metabolites, thereby improving piglet digestion and absorption.

Disequilibrium feeding pattern, as a new feeding technique, more suitable for egg-laying physiology, was feeding two-thirds diet to hens after 14:00 every day without modifying diet nutrient levels and changing daily feed rationing, to better meet calcium requirement of hens during eggshell formation. To verifying its application on eggshell quality of aged laying hens, 288 Hy-line laying hens (average body weight 2.03 ± 0.09 kg) at the age of 70 wk, as experimental birds, were randomly allocated into four groups (6 replicates/group, 12 hens/replicate); the experiment for eight weeks used a 2 × 2 arrangement with the factors- dietary calcium level (3.5% and 3.0%) and feeding pattern (equilibrium and disequilibrium), and univariate general linear model to analyze the main effects. The disequilibrium feeding decreased average daily feed intake (ADFI) (P < 0.001) and feed conversion ratio (FCR) (P < 0.001) of hens from the age of 71 to 74 wk. Low dietary calcium level decreased eggshell proportion (P = 0.007), eggshell strength (P = 0.046), and average eggshell thickness (P = 0.025) of hens at the age of 74 wk. Noticeably, the ultrastructure measurement of equatorial section confirmed that disequilibrium feeding increased eggshell thickness of hens at the age of 78 wk by increasing palisade layer thickness (P = 0.013) and mammillae layer thickness (P = 0.018). Disequilibrium feeding improved eggshell ultrastructure, possibly by increasing dietary calcium utilization. Decreased calcium excretion in feces during the daytime and increased calcium deposition in bones at night showed a positive correlation with increased bone mineral density at night by disequilibrium feeding (P < 0.05). These results were attributed to modified intestinal integrity, improved intestinal permeability and calcium absorption, which occurred through the increased thickness of duodenal mucus layer (P = 0.006), up-regulated mRNA expression of intestinal permeability-related genes occludin (P = 0.031) and MUC-2 (P = 0.002), and some involved intestinal bacteria such as decreased Parabacteroides (P = 0.007) and increased Lachnoclostridium (P = 0.017) being beneficial to calcium absorption strength and mucosal inflammation. Disequilibrium feeding pattern could improve eggshell quality, which may provide a protection for suitable reduction in dietary calcium level in aged laying hens, not affecting eggshell quality, but reducing intestinal burden and improving welfare.

This study was to evaluate how low phosphorus (P) diets affect growth performance and fecal P excretion in Xia-Nan cattle and to elucidate the underlying mechanisms. Thirty-two healthy Xia-Nan bulls with similar body weights (BW; 267.42 ± 45.77 kg) were assigned to four groups with eight individual replicate pens per group in a completely randomized block design, stratified by initial BW and average dry matter intake (DMI). Cattle were fed total mixed rations (concentrate-to-forage ratio 40:60) with varying dietary P levels (DM basis): 0.16% (XPA), 0.19% (XPB), 0.22% (XPC), and 0.25% (XPD; control) for 90 d. The first three groups were considered low-P treatments. Compared with the XPD group, XPA showed significantly lower average daily gain (ADG; P = 0.018) and DMI (P = 0.046), while XPB and XPC showed no differences (P > 0.05). XPB group showed a significant lower feed conversion ratio (FCR) than XPA (P = 0.049) and had the lowest FCR among all groups. Total-tract apparent digestibility of calcium (Ca; P = 0.006) and P (P = 0.006) decreased linearly with dietary P reduction. P intake (P < 0.001) and fecal P content (P < 0.001) were significantly lower in low-P groups than in the XPD group and decreased linearly with P reduction. Serum concentrations of parathormone hormone (PTH; P < 0.001), 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃; P = 0.005), Ca (P < 0.001), and P (P < 0.001) were positively correlated with decreasing dietary P levels, whereas calcitonin (CT; P = 0.016) and alkaline phosphatase (ALP; P = 0.006) were negatively correlated. XPB and XPD groups had higher molar proportions of propionate (P < 0.001) and butyrate (P = 0.006) but lower acetate molar proportion (P < 0.001) and acetate-to-propionate ratio (P < 0.001) than XPA. Fecal P excretion correlated positively with Ruminococcaceae_UCG-005, Saccharofermentans, and Butyrivibrio, and negatively with Rikenellaceae_RC9_gut_group and uncultured_bacteriumf_F082. These results suggest that reducing dietary P to 0.19% (XPB) maintained optimal growth performance while reducing environmental P pollution in Xia-Nan cattle.

In recent years, the use of insect meal in feed has been regarded as an important alternative to fishmeal. Defatted black soldier fly larvae meal (BSFLM), derived from Hermetia illucens, is a promising fishmeal alternative in aquafeeds for various aquatic species. However, its potential as a protein source in diets for the giant freshwater prawn (Macrobrachium rosenbergii) remains underexplored. This study provides a systematic evaluation of BSFLM as a fishmeal substitute in M. rosenbergii diets, assessing growth performance, nutrient digestibility, hepatopancreatic biochemistry, intestinal microbiota composition, and phosphorus discharge. Five isonitrogenous experimental diets were formulated, with BSFLM replacing 0 (control, BSFLM0), 10% (BSFLM10), 20% (BSFLM20), 40% (BSFLM40), or 80% (BSFLM80) of dietary fishmeal. A total of 900 juvenile prawns (initial weight 0.25 ± 0.03 g, 40-d-old) were fed experimental diets. They were reared in 300-L tanks (60 prawns/tank, 3 replicates/group) and fed to satiation twice daily for 8 weeks. Each tank was treated as an independent experimental unit for statistical analysis. Growth performance (survival, weight gain, and feed conversion ratio) did not differ significantly among groups (P > 0.05). BSFLM40 and BSFLM80 groups showed significantly improved phosphorus retention efficiency (14.57% to 19.24%) and deposition rate (13.69% to 18.16%), alongside reduced phosphorus waste (P < 0.05). Intestinal digestive enzyme activities (trypsin, amylase, and lipase) were significantly upregulated at 40% to 80% BSFLM inclusion (P < 0.05). BSFLM-fed prawns exhibited enhanced antioxidant capacity (total superoxide dismutase activity was significantly elevated, P < 0.001) with stable hepatopancreatic malondialdehyde levels (P = 0.343). Transcriptomic analysis revealed differential expression of nutrient metabolism (involving in the insulin signaling pathway and mineral absorption pathway) and immune response genes (associating with phagosome activity and antigen processing/presentation) in BSFLM20 vs. control. BSFLM inclusion altered intestinal microbiota: BSFLM10 enriched Firmicutes abundance, while BSFLM40 increased Agromyces abundance (P < 0.05). BSFLM-fed prawns displayed enhanced intestinal morphology (villus height and muscularis thickness increased, P < 0.001). In summary, BSFLM can replace up to 80% of fishmeal in M. rosenbergii diets without compromising growth. Moderate replacement (10% to 20%) enhanced antioxidant capacity and optimized microbiota; higher levels (40% to 80%) improved digestive function, reduced phosphorus discharge, and stimulated chitinolytic bacteria, confirming BSFLM as a nutritionally balanced and environmentally sustainable fishmeal alternative in M. rosenbergii aquaculture.

Inulin, a natural dietary fiber, confers multiple physiological benefits. However, the effects of inulin on the liver and intestinal health of broilers remain unclear. The study investigated the effects and mechanisms of inulin supplementation on hepatic and intestinal health of broilers. A total of 192 male broilers (821.15 ± 14.99 g) at 21 d of age were randomly allocated to four treatment groups, comprising eight replicates per group with six broilers each. The dietary treatments included: a control group (CON) receiving a basal diet and three treatment groups fed the basal diet supplemented with 0.5, 1.0, or 2.0 g/kg inulin (designated as INU-0.5, INU-1.0, and INU-2.0, respectively). Results indicated that dietary inulin supplementation elicited a quadratic response in final body weight (FBW, P = 0.032). Inulin supplementation produced linear improvements in average daily gain (ADG, P = 0.044) alongside quadratic reductions in both average daily feed intake (ADFI) and feed-to-gain ratio (F/G ratio) (P < 0.001). Notably, inulin supplementation linearly decreased malondialdehyde (MDA) levels (P < 0.001) while significantly enhancing superoxide dismutase (SOD) activity (P < 0.001). Furthermore, inulin supplementation demonstrated dose-dependent effects on lipid metabolism, including a linear reduction in abdominal fat deposition (P < 0.001), decreased hepatic and serum concentrations of total cholesterol (TCHO, both P < 0.001) and triglycerides (TG, P < 0.001 and P = 0.001, respectively), and reduced serum levels of both high-density lipoprotein (HDL, P = 0.010) and low-density lipoprotein (LDL, P < 0.001) (P < 0.01). Parallel improvements in intestinal barrier function were observed, with linear increases in jejunal expression of tight junction proteins (claudin-5, occludin, and zonula occludens-1 [ZO-1]), mucin 2 (MUC2), and diamine oxidase (DAO) (P < 0.001). Additionally, inulin supplementation selectively increased the abundances of key microbes, including Bacteroides, Lactobacillus, and Akkermansia, while decreased the abundances of Alistipes, Odoribacte, Parabacteroides, Rikenella, and Erysipelatoclostridium (P < 0.001). These microbial shifts were associated with modulation of key metabolic pathways, including taurine and hypotaurine metabolism, purine metabolism, arginine and proline, and phenylalanine metabolism. Collectively, these findings demonstrate that inulin supplementation enhances broiler productivity while improving both intestinal and hepatic health (P < 0.05) through microbiota-mediated metabolic regulation. Therefore, dietary inulin supplementation would be a recommendable nutritional strategy to optimize production efficiency in commercial broiler industry.

Chrysanthemum stalks (CS), a plant by-product, often face underutilization and resource wastage. This study aimed to explore the effects of partially replacing peanut vines (PV) in the diet with CS on the growth performance, rumen fermentation performance and microbiota, as well as the plasma physiology, biochemistry, and metabolism of Hu sheep. Twenty-seven 6-month-old male Hu sheep (weighing 39.4 ± 0.5 kg; mean ± SD) were randomly assigned to three groups: 1) basal diet (CON); 2) CS replaced 7.88% of PV (low substitution [LS]); and 3) CS replaced 15.57% of PV (high substitution [HS]). The feeding trial lasted for 91 d. Replacement of peanut vines with chrysanthemum stalks significantly increased dry matter intake in both LS and HS groups as compared to the CON group (P = 0.021; linear effect, P = 0.050), while average daily weight gain only increased significantly in the LS group (P = 0.020; quadratic P = 0.042). The concentrations of volatile fatty acids (VFAs) and ammonia nitrogen (NH₃-N) were the highest in rumen of LS group (P < 0.05; quadratic effect, P < 0.05). The LS group also had the highest relative abundance of Prevotella (P = 0.011; quadratic P = 0.001). The rumen metabolomic analysis showed elevated levels of flavonoids, terpenoids, and amino acids in the LS group (P < 0.05). Additionally, the LS group exhibited significantly higher levels of total antioxidant capacity, immunoglobulin A, and immunoglobulin M (P < 0.05; quadratic P < 0.05), while tumor necrosis factor-α and interferon-γ levels were lower (P < 0.05; quadratic P < 0.05). The plasma metabolomic analysis revealed increases in phospholipids, amino acids, and indole derivatives in the LS group (P < 0.05). In general, CS improved the growth performance of Hu sheep by increasing VFA concentrations and promoting beneficial bacteria like Prevotella in the rumen. Additionally, flavonoids and terpenoids in CS were positively associated with immune response and antioxidant capacity. These beneficial effects were more pronounced in the LS group compared to the HS group, highlighting the potential of CS as a roughage substitute for improving sheep growth performance and immune function.

Choline is an essential nutrient for fish, and its metabolites are components of all membrane systems. Membrane phospholipids play an important role in maintaining the morphology and function of mitochondria, which could affect the growth and development of myofiber. To evaluate the effects of choline on growth performance, muscle fiber development, and mitochondrial morphology and function in grass carp, six diets containing graded choline levels [154.0 (basal diet), 321.8, 672.2, 1024.9, 1373.2, and 1722.8 mg/kg] were fed to 450 sub-adult grass carp (583.44 ± 1.65 g) for 56 d. The fish were divided into six groups with three replicates of 25 fish each. The results showed as follows: 1) compared with the control group, choline increased the growth performance, muscle protein content and choline deposition in sub-adult grass carp (P < 0.05), while decreased adhesive force (P < 0.001) and cooking loss (P = 0.037), thus improving fish flesh quality. 2) Dietary choline levels of 1024.9 to 1373.2 mg/kg significantly increased the frequency of myofibers with diameter >100 μm (P = 0.002) and fusion coefficient (P < 0.001). The mRNA expression of MyoG (P < 0.001), MyoD (P < 0.001), Myf5 (P = 0.005), MRF4 (P = 0.028), MYHC (P = 0.005), and myomaker (P < 0.001) increased quadratically with dietary choline, whereas MSTN expression was non-significantly lower than controls at 1024.9 to 1373.2 mg/kg (P = 0.078). Furthermore, choline increased the mRNA expression of IGF1, PI3K, AKT, and TOR (P < 0.05) and decreased the mRNA expression of FoxO3a and MuRF1 (P < 0.05). 3) Muscle adenosine triphosphate (ATP) content (P < 0.001), protein levels of NDUFV1 (P = 0.004) and ATP5A1 (P = 0.046), and the mRNA levels of NRF1 (P = 0.017), TFAM (P = 0.014), and OPA1 (P < 0.001) were increased quadratically. Conversely, the mRNA levels of DRP1 (P < 0.001), PINK (P < 0.001), and PARKIN (P = 0.002) were decreased quadratically. 4) According to the quadratic regression analysis of percent weight gain (PWG) and muscle ATP content, the choline requirement of sub-adult grass carp was 951.2 and 1084.9 mg/kg diet, respectively. In summary, optimal levels of dietary choline improved the myofiber hypertrophy in grass carp, which was associated with upregulation of myogenesis regulator and the activation of the IGF1/PI3K/AKT signaling pathway, and maintained mitochondrial stability probably via regulating mitochondrial quality control.