This study was to evaluate the effect of supplementing the diet of broilers with Neolamarckia cadamba leaf extract (NCLE) on meat quality by evaluating antioxidant parameters and the expression of genes in the p38 mitogen-activated protein kinase/nuclear factor-erythroid 2-related factor 2/antioxidant responsive element (p38 MAPK/Nrf2/ARE) signaling pathway, coupled with LC–MS-based metabolomic analysis. A total of 480 one-day-old male broilers were randomly allocated to four treatment groups—a control (CON) group, which was fed a basal diet, and three NCLE treatment groups, which were fed the basal diet supplemented with 100, 200, or 400 mg/kg NCLE (N1, N2, and N3 groups, respectively) for 42 d. Compared with the CON group, meat quality was improved in the N2 and N3 groups, as evidenced by the higher pH_45min (P < 0.05) and lower shear force (P < 0.05) in breast muscle (BM) and lower drip loss at 48 h (P < 0.05) in leg muscle (LM). Moreover, BM antioxidant capacity was significantly enhanced in the N3 group, characterized by an increase in the total antioxidant capacity (T-AOC), the concentrations of glutathione peroxidase (GSH-Px) and catalase (CAT), and the relative mRNA expression of p38 MAPK, extracellular-signal regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), Nrf2, CAT, and GSH-Px (P < 0.05). Similarly, LM in the N3 group displayed higher T-AOC, increased GSH-Px and CAT concentrations, reduced malonaldehyde contents (P < 0.05), and upregulation of the relative mRNA levels of JNK, Nrf2, heme oxygenase, CAT, and superoxide dismutase (SOD) (P < 0.05). Metabolomics analysis revealed that D-arabinono-1,4-lactone and lyso-PAF C-16-d4 were negatively correlated with shear force and cooking loss (P < 0.05) and displayed increased abundance in BM of the N3 group. L-Serine levels were upregulated while D-fructose 1,6-diphosphate contents were downregulated in the three NCLE groups. Finally, the differential metabolites in both BM and LM were involved in amino acid metabolism pathways. Our results indicated that NCLE supplementation improved meat quality by enhancing antioxidant enzyme activities, promoting the expression of genes in the p38 MAPK/Nrf2/ARE signaling pathway, and regulating amino acid metabolism. The optimal NCLE concentration was found to be 400 mg/kg.

Thirty-two primiparous and 31 multiparous Alpine goats were used to determine influences of diets varying in level and source of forage on performance in early to mid-lactation for 16 wk. Diets consisted of 40%, 50%, 60%, and 70% forage (designated as 40F, 50F, 60F, and 70F, respectively) with 60F and 70F containing coarsely ground grass hay (primarily orchardgrass) and 40F and 50F containing cottonseed hulls, alfalfa pellets, and coarsely ground wheat hay. Diets contained 15.9% to 16.3% crude protein and 37.8%, 42.1%, 53.5%, and 55.4% neutral detergent fiber (NDF) with 10.0%, 15.8%, 50.1%, and 55.5% particle retention on a 19-mm sieve, and 26.1%, 29.6%, 38.3%, and 40.0% physically effective NDF (peNDF) for 40F, 50F, 60F, and 70F, respectively. Dry matter intake (2.71, 2.75, 1.96, and 1.95 kg/d) and milk yield (2.82, 2.71, 2.23, and 2.10 kg/d for 40F, 50F, 60F, and 70F, respectively) were lower (P < 0.05) for the two diets highest in forage. Digestion of organic matter was similar among diets (P > 0.05), but digestibility of NDF was greater (P < 0.05) for 60F and 70F (57.5%, 58.4%, 68.9%, and 72.2% for 40F, 50F, 60F, and 70F, respectively). Diet affected (P < 0.05) milk fat (3.16%, 3.37%, 2.93%, and 2.97%) and protein concentrations (2.62%, 2.69%, 2.58%, and 2.52% for 40F, 50F, 60F, and 70F, respectively). Milk energy yield was greater (P < 0.05) for the two diets lowest in forage (7.51, 7.45, 5.68, and 5.34 MJ/d), although yield relative to dry matter intake was not affected (P > 0.05) by diet and was lower (P < 0.05) for primiparous vs. multiparous goats (2.71 and 3.09 MJ/kg). Ruminal pH and acetate proportion were greater for 60F and 70F than for the other diets and the proportion of butyrate was lower for the two diets highest in fiber. The mean lengths of time spent ruminating, eating, standing, and lying were not affected (P > 0.05) by diet or parity, but many interactions involving diet, period, hour, and parity were significant (P < 0.05). In conclusion, lactational performance of Alpine goats in early to mid-lactation will be constrained with diets high in forage of moderate quality, peNDF content, and large particle size, which appeared related to limited feed intake.

Mastitis affects almost all mammals including humans and dairy cows. In the dairy industry, bovine mastitis is a disease with a persistently high incidence, causing serious losses to the health of cows, the quality of dairy products, and the economy of dairy farms. Although local udder infection caused by the invasion of exogenous pathogens into the mammary gland was considered the main cause of mastitis, evidence has been established and continues to grow, showing that nutrition factors and gastrointestinal microbiome (GM) as well as their metabolites are also involved in the development of mammary inflammatory response. Suboptimal nutrition is recognized as a risk factor for increased susceptibility to mastitis in cattle, in particular the negative energy balance. The majority of data regarding nutrition and bovine mastitis involves micronutrients. In addition, the dysbiotic GM can directly trigger or aggravate mastitis through entero-mammary gland pathway. The decreased beneficial commensal bacteria, lowered bacterial diversity, and increased pathogens as well as proinflammatory metabolites are found in both the milk and gastrointestinal tract of mastitic dairy cows. This review discussed the relationship between the nutrition (energy and micronutrient levels) and mastitis, summarized the role of GM and metabolites in regulating mastitis. Meanwhile, several non-antibiotics strategies were provided for the prevention and alleviation of mastitis, including micronutrients, probiotics, short-chain fatty acids, high-fiber diet, inulin, and aryl hydrocarbon receptor.

This study aimed to investigate the effects of different proportions of dietary fermented sweet potato residue (FSPR) supplementation as a substitute for corn on the nutrient digestibility, meat quality, and intestinal microbes of yellow-feathered broilers. Experiment 1 (force-feeding) evaluated the nutrient composition and digestibility of mixtures with different proportions of sweet potato residue (70%, 80%, 90%, and 100%) before and after fermentation. In Experiment 2 (metabolic growth), a total of 420 one-day-old yellow-feathered broilers were randomly allocated to 4 groups and fed corn-soybean meal-based diets with 0, 5%, 8%, and 10% FSPR as a substitute for corn. The force-feeding and metabolic growth experiments were performed for 9 and 70 d, respectively. The treatment of 70% sweet potato residue (after fermentation) had the highest levels of crude protein, ether extract, and crude fiber and improved the digestibility of crude protein and amino acids (P < 0.05). Although dietary FSPR supplementation at different levels had no significant effect on growth performance and intestinal morphology, it improved slaughter rate, half-chamber rate, full clearance rate, and meat color, as well as reduced cooking loss in the breast and thigh muscles (P < 0.05). Dietary supplementation with 8% and 10% FSPR increased the serum immunoglobulin M and immunoglobulin G levels in broilers (P < 0.05). Furthermore, 10% FSPR increased the Shannon index and Ruminococcaceae_UCG-014, Ruminococcaceae_UCG-010 and Romboutsia abundances and decreased Sutterella and Megamonas abundances (P < 0.05). Spearman's correlation analysis showed that meat color was positively correlated with Ruminococcaceae_UCG-014 (P < 0.05) and negatively correlated with Megamonas (P < 0.05). Collectively, 70% sweet potato residue (after fermentation) had the best nutritional value and nutrient digestibility. Dietary supplementation with 8% to 10% FSPR as a substitute for corn can improve the slaughter performance, meat quality, and intestinal microbe profiles of broilers. Our findings suggest that FSPR has the potential to be used as a substitute for corn-soybean meals to improve the meat quality and intestinal health of broilers.

The use of antibiotics in animal production raises great public safety concerns; therefore, there is an urgent need for the development of substitutes for antibiotics. In recent decades, plant-derived feed additives have been widely investigated as antibiotic alternatives for use in animal health and production because they exert multiple biological functions and are less likely to induce resistance development. This review summarizes the research history and classification of phytogenic feed additives and their main functions, potential modes of action, influencing factors, and potential negative effects. Further, we highlight the challenges in developing sustainable, safe, and affordable plant-derived antibiotic alternatives for use in livestock production.

Fructo-oligosaccharides (FOS) are well-known prebiotics that have the potential to improve sow reproductive performance and increase piglet growth. However, previous studies were observed in sole FOS-supplemented diets of sows or weaned piglets and did not consider the sow-to-piglet transfer effect on the performance and diarrhea rate of weaned piglets. This study explores the effects of dietary FOS supplementation on the reproductive performance of sows, and the effects of FOS supplementation at different stages on the growth performance and diarrhea rate of weaned piglets. A split-plot experimental design was used with sow diet effect in the whole plot and differing piglet diet effect in the subplot. Fifty-two multiparous sows (223.24 ± 14.77 kg) were randomly divided into 2 groups (0 or 0.2% FOS). The experiment lasted from day 85 of gestation to day 21 of lactation. Reproductive performance, glucose tolerance, placental angiogenesis, and intestinal flora of sows were assessed. At weaning, 192 weaned piglets were grouped in 2 × 2 factorial designs, with the main effects of FOS supplemental level of sow diet (0 and 0.2%), and FOS supplemental level of weaned piglet diet (0 and 0.2%), respectively. The growth performance and diarrhea rate of the weaned piglets were analyzed during a 28-d experiment. Maternal dietary supplementation of FOS was shown to reduce the stillbirth and invalid piglet rates (P < 0.05), improve the insulin sensitivity (P < 0.05) and fecal scores (P < 0.05) of sows, increase the abundance of Akkermansia muciniphila (P = 0.016), decrease the abundance of Escherichia coli (P = 0.035), and increase the isovalerate content in feces (P = 0.086). Meanwhile, the placental angiogenesis marker CD31 expression was increased in sows fed FOS diet (P < 0.05). Moreover, maternal and post-weaning dietary FOS supplementation reduced the diarrhea rate of weaned piglets (P < 0.05) and increased the content of short-chain fatty acids in feces (P < 0.05). Furthermore, only post-weaning dietary FOS supplementation could improve nutrient digestibility of weaned piglets (P < 0.05). Collectively, FOS supplementation in sows can reduce stillbirth rate, perinatal constipation, and insulin resistance, as well as improve placental vascularization barrier. Additionally, maternal and post-weaning dietary FOS supplementation reduced the diarrhea rate of weaned piglets, but only FOS supplementation in piglets alone at weaning stage could improve their nutrient digestibility.

The use of next-generation probiotics (NGP) in pigs for combating diseases has been subject to limited research. Here we explored the potential of a well-known NGP candidate Akkermansia muciniphila targeting pig gut health. In the first screening experiment, we found that the abundance of A. muciniphila peaked at 14 d old but decreased at weaning (21 d old; P < 0.05), suggesting the weaning period may be an effective window for A. muciniphila intervention. Following that, 48 crossbred weaned pigs at 28 d old were randomly assigned to five groups: control (CON), high/low live A. muciniphila (HA/LA), and high/low heat-killed A. muciniphila (HIA/LIA). From 1 to 28 d old, the CON group received gastric infusion of anaerobic sterile saline every other day; the HA and LA groups were gavaged every other day with 1 × 10¹⁰ CFU/5 mL and 5 × 10⁸ CFU/5 mL live A. muciniphila, respectively; and the HIA and LIA groups were gavaged every other day with 1 × 10¹⁰ CFU/5 mL and 5 × 10⁸ CFU/5 mL heat-killed A. muciniphila, respectively. At d 29, pigs in the CON group were randomly and equally divided into two groups, one of which was named the enterotoxigenic Escherichia coli (ETEC) group, and all groups except CON received a 5-d ETEC challenge. The supplementation of A. muciniphila numerically reduced the diarrhea rate of weaned pigs compared to the pigs that only received the ETEC challenge (P = 0.57), but the LIA group had a higher diarrhea rate than the CON group (P < 0.05). Consistent with this, the supplementation of A. muciniphila improved the small intestinal morphology and structure, proportion of CD4⁺ T lymphocytes in the blood, as well as the expression of genes related to intestinal barrier and antioxidant indices of pigs with ETEC challenge, especially for the LA group (P < 0.05). Meanwhile, A. muciniphila supplementation reduced the expression of ETEC virulence factor genes in the ileum and colon of pigs challenged by ETEC (P < 0.05). Therefore, A. muciniphila may protect the intestinal health of weaned piglets from damage caused by ETEC infection, but the effect may vary depending on the concentration and activity of A. muciniphila.

A feeding trial was conducted to assess the impacts of dietary astaxanthin from wall-broken Haematococcus pluvialis (WBHPA) on the growth performance, antioxidant status, immune response, and intestinal health of rainbow trout (Oncorhynchus mykiss). Six experimental diets were formulated with various concentrations of WBHPA, ranging from 0 to 8.4 g/kg (containing 0 to 125 mg/kg astaxanthin). Each diet was fed to triplicate groups of rainbow trout (mean initial weight of 561 g) twice daily for 9 consecutive weeks. The survival rate and feed intake of fish exhibited no significant differences among the dietary groups (P > 0.05). Similarly, dietary inclusion of 25 to 100 mg/kg astaxanthin did not significantly affect the weight gain and daily growth coefficient (P > 0.05), but excessive inclusion of astaxanthin (125 mg/kg) slightly depressed these parameters (P < 0.05). Dietary inclusion of 25 to 50 mg/kg astaxanthin increased the activities of intestinal digestion and absorption enzymes (lipase, creatine kinase, and alkaline phosphatase), while the inclusion of 25 to 75 mg/kg astaxanthin improved the immune response of fish. Furthermore, regardless of inclusion level (25 to 125 mg/kg), dietary astaxanthin supplementation strengthened the intestinal mucosal barrier function and improved antioxidant activity, thereby promoting intestinal development. Conclusively, 25 to 75 mg/kg astaxanthin from WBHPA was recommended to be included in diets for rainbow trout.

In markets for beef and sheep meat, an appropriate level of intramuscular fat (IMF) is highly desirable for meat-eating quality, but strategies to improve it usually lead to an undesirable excess in carcase fat, presenting a major challenge to livestock producers. To solve this problem, we need to understand the partitioning of fat among the major fat depots: IMF, subcutaneous fat (SCF) and visceral fat (VF). In most genotypes of cattle and sheep, the rate of accretion is lower for IMF than for SCF and VF, so genetic selection for a high level of IMF, or the use of an increased dietary energy supply to promote IMF deposition, will increase overall fatness and feed costs. On the other hand, feeding postnatal calves with excessive concentrates promotes IMF deposition, so a nutritional strategy is feasible. With genetic strategies, several problems arise: 1) positive genetic correlations between IMF, SCF and VF differ among genotypes in both cattle and sheep; 2) genotypes appear to have specific, characteristic rates of accretion of IMF during periods of growth and fattening; 3) most breeds of cattle and sheep naturally produce meat with relatively low levels of IMF, but IMF does vary substantially among individuals and breeds so progress is possible through accurate measurement of IMF. Therefore, an essential prerequisite for selection will be knowledge of the genetic correlations and fat accretion rates for each genotype. Currently, selection for IMF is based on existing technology that directly measures IMF in the progeny or siblings, or estimates IMF in live animals. New technology is needed to permit the simultaneous measurement of SCF and IMF in the field, thus opening up the possibility of accurate selection, particularly for fat partitioning in live animals. Specifically, there would be great value in detecting individuals with an IMF advantage at an early age so the generation interval could be shortened and genetic gain accelerated. Genetic gain would also be greatly aided if we could select for genes that control adipogenesis and lipogenesis and are also differentially expressed in the various depots.

A proper dietary electrolyte balance (dEB) is essential to ensure optimal growth performance of piglets. In the low-protein diet, this balance may be affected by the reduction of soybean meal and the inclusion of high levels of synthetic amino acids. The objective of this experiment was to evaluate the optimal dEB of low-protein diets and its impact on the growth performance of piglets. A total of 108 piglets (initial age of 35 d) were randomly divided into 3 groups with 6 replicates of 6 pigs each as follows: low electrolyte diet (LE group; dEB = 150 milliequivalents [mEq]/kg); medium electrolyte diet (ME group; dEB = 250 mEq/kg); high electrolyte diet (HE group; dEB = 350 mEq/kg). Results indicated that the LE and HE diet significantly decreased the average daily gain, average daily feed intake, and crude protein digestibility (P < 0.05) in piglets. Meanwhile, LE diets disrupted the structural integrity of the piglets' intestines and decreased jejunal tight junction protein (occludin and claudin-1) expression (P < 0.05). Additionally, the pH and HCO₃^– in the arterial blood of piglets in the LE group were lower than those in the ME and HE groups (P < 0.05). Interestingly, the LE diet significantly increased lysine content in piglet serum (P < 0.05), decreased the levels of arginine, leucine, glutamic acid, and alanine (P < 0.05), and inhibited the mammalian target of rapamycin complex 1 (mTORC1) pathway by decreasing the phosphorylation abundance of key proteins. In summary, the dietary electrolyte imbalance could inhibit the activation of the mTORC1 signaling pathway, which might be a key factor in the influence of the dEB on piglet growth performance and intestinal health. Moreover, second-order polynomial (quadratic) regression analysis showed that the optimal dEB of piglets in the low-protein diet was 250 to 265 mEq/kg.