This study addressed the escalating demand for aquatic feed by exploring the potential of alfalfa nutrient concentrate (ANC) as feed ingredient for rainbow trout. Test diets contained varying ANC levels (0%, 5%, 10%, 15%, and 20%) to replace fishmeal (32% in the 0% ANC diet) to achieve equal digestible protein and were processed using a cooking extrusion method. Analysis of feed pellets showed that pellet density increased with ANC levels (P < 0.001), resulting in sinking pellets at 20% ANC. Water stability and durability were improved while oil leakage decreased with increasing ANC levels (P < 0.05). Two feeding trials were conducted to test the diets in flow-through water systems with three replicates per diet. The first 10-week trial evaluated their impact on feeding, fecal physical quality, and the apparent digestibility coefficient (ADC) of dietary nutrients in rainbow trout (initial body weight 18.0 ± 0.2 g). ANC inclusion did not impact the palatability and satiety feed intake of the fish (P > 0.05). However, the ADC of dry matter and phosphorus significantly decreased in fish fed the 20% ANC diet (P < 0.05). The second 9-week trial investigated the growth performance, nutrition quality, and metabolism of rainbow trout (initial body weight 19.0 ± 0.2 g). While all fish exhibited substantial growth, fish fed diets with 10% to 20% ANC displayed lower specific growth rate and higher feed conversion ratio compared to those fed with 0% or 5% ANC (P < 0.05). The whole body protein content was higher in fish fed 5% ANC compared to all other treatments (P = 0.030). The biochemical parameters of plasma were similar across treatments, except for a decrease in plasma phosphorus levels in fish fed a 10% ANC diet compared to those fed a 0% ANC diet (P = 0.033). Significant changes were observed in liver metabolism including tricarboxylic acid cycle, amino acid and energy metabolism pathways in fish fed the 20% ANC diet versus the 0% ANC diet (P < 0.05). These results demonstrate that ANC inclusion improved pellet physical quality without impairing feeding behavior and nutritional quality of the fish but inclusion ≥10% in the diet reduced fish growth. This study offers the first comprehensive assessment of the potential of ANC used in fish feed involving feed management, feeding evaluation, and the biological response.

Nutrition consistently affects microbe-host interactions in the gastrointestinal tract. This study aimed to unravel how undernutrition reshapes the microbial composition and the homeostasis of epithelium in the jejunum and ileum. Sixteen late-gestation Hu-sheep were randomly assigned to the control group (n = 8, 100% ad libitum feeding levels) or the undernutrition group (n = 8, which received 30% ad libitum feeding levels). After 15-d treatment, all ewes were slaughtered, and jejunal and ileal digesta and epithelium samples were collected for 16S rRNA gene sequencing and transcriptome sequencing, respectively. Results indicated that undernutrition decreased the jejunal and ileal tissue weights (P = 0.005 and P = 0.022) and the levels of volatile fatty acids (P = 0.019 and P = 0.007) and microbial protein levels (P = 0.019 and P = 0.031) in jejunal and ileal digesta. The relative abundance of acetate producing microbiota, including Clostridia UCG-014 norank, Ruminococcus, [Ruminococcus] gauvreauii, and Lachnospiraceae_Blautia, were significantly reduced (P < 0.05) in the jejunum and ileum. Undernutrition up-regulated (P < 0.05) the expression of genes involved in amino acid synthesis and fatty acid oxidation, but down-regulated (P < 0.05) the expression of genes associated with amino acid degradation, fatty acid synthesis, and extracellular structures in jejunal and ileal epithelium. In the jejunal epithelium, genes associated with extracellular matrix–receptor interactions, cell growth, and immune response were down-regulated (P < 0.05) upon undernutrition. Taken together, undernutrition changed the microbial community in the jejunum and ileum, which altered the fermentation mode and the production of volatile fatty acids and microbial protein. These affected the energy and protein system in the epithelium and reprogrammed substance metabolism and extracellular structures, which probably further influenced cell growth and immune response. These insights provide a foundation for completely clarifying the crosstalk between small intestinal microbiota and the host.

The synchronized absorption of amino acids and glucose in the gut is essential for amino acid utilization and protein synthesis in the body. The study aimed to investigate how the starch digestion rate and amino acid levels impact the growth and intestinal starch and amino acid digestion, transport, and metabolism in juvenile broilers. The experiment was conducted with 702 Arbor Acres Plus broilers at 1 d old, which were randomly divided into 9 treatments with 6 replicates of 13 chickens each. The treatments included 3 different starch sources (corn, waxy corn, and tapioca) with 3 different apparent ileal digestible lysine (AID Lys) levels (1.08%, 1.20%, and 1.32%). A notable interaction was noted for dietary starch sources and AID Lys levels in the feed-to-gain ratio (F/G) and distal ileal starch digestibility (P < 0.01). The tapioca starch and waxy corn starch diets with 1.32% of AID Lys significantly decreased F/G compared with corn starch (P < 0.01). There was no significant difference in F/G of broilers among waxy corn starch diet with 1.08% AID Lys level, tapioca starch diet with 1.20% AID Lys level, and corn starch diet with 1.32% AID Lys level (P > 0.05). The 1.32% AID Lys level and the waxy corn starch both improved the body weight (BW) of broilers from 0 to 3 weeks of age, intestinal starch digestibility, and intestinal villi height or the ratio of villi height to crypt depth (P < 0.05). Compared with the corn starch diet, waxy corn starch and tapioca starch diets significantly elevated the AID of Met, Glu, Lys, Arg, Asp, His, Ile, Tyr, Gly, and Val levels (P < 0.05). The carbon metabolomics results revealed that the waxy corn starch diet significantly reduced malic acid and cis-aconitic acid levels (P < 0.05) in the tricarboxylic acid cycle compared to the corn starch diet. It was concluded that a waxy corn starch diet improves the growth performance of broilers by improving intestinal morphology, increasing the absorption and transport of amino acids, reducing the amino acid oxidation for energy supply in the intestinal mucosa, and promoting protein synthesis in muscles, which not only reduces the need for dietary AID Lys but also saves on production costs.

Feeding frequency represents a potential strategy to improve the utilization of protein sources by fish. This study investigated its impact on the utilization of protein blend in gibel carp. The dietary fishmeal was totally substituted with three protein blends consisting of Tenebrio molitor meal, Chlorella meal, Clostridium autoethanogenum protein, cottonseed protein concentrate, at ratios of 1:1:8:2, 1:1:6:4, and 1:1:4:6, respectively. During an 8-week feeding trial, a total of 960 healthy fish (18.10 g) were randomly assigned to eight groups, each with three replicates. Then they were fed either twice daily (two meals per day) or four times daily (four meals per day) with four different diets. Higher feeding frequency increased feed intake and intestinal trypsin activity (P < 0.05), and up-regulated the expression levels of genes related to amino acid or peptide transporter (pept1, y⁺lat2) and sensory receptors (casr, gprc6a, mglur4) in intestine (P < 0.05). Moreover, it accelerated muscle protein turnover by increasing free amino acid content, aspartate aminotransferase activity and akt1 transcript levels (P < 0.05), ultimately promoting growth. However, higher feeding frequency reduced protein apparent digestibility and feed efficiency (P < 0.05). Dietary blended proteins elevated trypsin and chymotrypsin activities (P < 0.01). Notably, the adverse effects observed with blended proteins (ratio at 1:1:8:2) on total essential amino acid digestibility and muscle protein metabolism-related gene expression were mitigated with increased feeding frequency, thus alleviating growth inhibition. Furthermore, the blended proteins at a ratio of 1:1:6:4 increased protein apparent digestibility (P < 0.05), down-regulated mstn expression level (P < 0.05), and up-regulated expression levels of genes related to protein synthesis (akt1, mtor, s6k1, eif4b, eif4e; P < 0.05); thereby promoting protein utilization and muscle growth at four meals per day. Overall, feeding frequency interacted synergistically with blended proteins to influence growth and protein utilization in gibel carp, and a protein blend with a ratio of 1:1:6:4 was a superior alternative to fishmeal at both feeding frequencies. Future strategies aimed at replacing dietary fishmeal should consider the role of feeding frequency as a critical factor.

Gut microbiota disruption during the weaning process is a significant factor of intestinal injury. Our previous studies have suggested that Prevotella may play a critical role in causing intestinal inflammation. This study aimed to clarify the impact of Prevotella copri on intestinal injury and the protecting effect by dihydroquercetin (DHQ) in weaned piglets. A total of 108 healthy Duroc × Landrace × Yorkshire weaned piglets, aged 21 d, were randomly allocated into 3 groups with 6 replicates and 6 piglets per replicate. The piglets were the following diets for 28 d: 1) a basal diet, 2) basal diet containing 1.0 × 10⁸ CFU/kg P. copri, 3) basal diet supplemented with 1.0 × 10⁸ CFU/kg P. copri and 100 mg/kg DHQ. Results showed that P. copri decreased significantly the average daily gain (ADG) (P < 0.001), which was recovered by supplementation of DHQ with decreased serum levels of malondialdehyde (MDA), interleukin (IL)-2 and IL-8 but increased total superoxide dismutase (T-SOD) activity and IL-10 in weaned piglets (P < 0.001). Moreover, DHQ increased the expression of tight junction proteins (claudin-2, occludin and tight junction protein zonula occludens protein-1 (ZO-1) and the mRNA expression of glutathione peroxidase 4 (GPX-4) in ileum (P < 0.001). Intestinal flora analysis showed that P. copri increased the relative abundance of Prevotella (P = 0.026) and Eubacterium coprostanoligenes group (P < 0.001), but decreased the relative abundance of Lachnospiraceae NK4A136 group (P < 0.001), while supplementation of DHQ reduced the relative abundance of Prevotella (P = 0.026). Metabolomics results indicated that P. copri enhanced the content of 12-OH bile acid, but decreased the contents of glycodeoxycholic acid (GDCA) and glycochenodeoxycholic acid (GCDCA) (P < 0.001), while DHQ reduced the 12-OH bile acid content (P < 0.001) and increased the GDCA content (P = 0.020). In summary, P. copri caused intestinal injury and reduced growth performance in weaned piglets, and DHQ showed a protective effect by modulating gut microbiota and bile acids metabolism.

This study was to evaluate the effects of rapeseed (Brassica napus L.) from China with different content of glucosinolate (Gls) and erucic acid (EA) on laying hens. A total of 600 laying hens at 33 wk of age were randomly divided into 5 treatments containing a control diet and 4 diets with 11.5% rapeseed. The 11.5% rapeseed diets varied in Gls and EA levels: 1) Deyou no. 6 (DY6) with Gls at 22.67 μmol/g and EA at 0.7%, 2) Mianbangyou no. 1 (MB1) with Gls at 43.23 μmol/g and EA at 3.5%, 3) Deyou no. 5 (DY5) with Gls at 74.66 μmol/g and EA at 16.20%, 4) Xiheyou no. 3 (XH3) with Gls at 132.83 μmol/g and EA at 44.60%. Each group had eight replicates and each replicate had 15 hens. The trial lasted for 12 wk with 4 wk withdrawal. From 1 to 8 wk of the trial, 11.5% rapeseed reduced average daily feed intake (ADFI) compared to the control group (P = 0.002), and egg-laying rate of XH3 rapeseed was lower than that of DY6 rapeseed (P = 0.006), and egg weight of MB1, DY5, and XH3 rapeseed were lower than that of the control group (P = 0.007). Egg mass was reduced by 11.5% rapeseed and egg mass of XH3 and DY5 rapeseed were lower than that of DY6 rapeseed (P = 0.004). Feed conversion ratio (FCR) of 11.5% rapeseed was higher than that the control group and FCR was higher in XH3 rapeseed than in DY6 rapeseed from 1 to 8 wk (P = 0.008). At wk 8, the lightness value of eggshell color of XH3 rapeseed was significantly lower than that of the control and DY5 rapeseed (P = 0.012). Xiheyou no. 3 rapeseed had a higher redness value of eggshell color than the control and MB1 and DY5 rapeseed (P = 0.008). Albumen height of DY5 rapeseed was lower than that of the control group at wk 8 (P = 0.012). Mianbangyou no. 1 and DY5 rapeseed decreased Haugh unit at wk 4 and 8, respectively (P = 0.011, P = 0.024). Serum estradiol (E2) content was decreased by 11.5% rapeseed (P = 0.003). Thyroid index increased as the Gls and EA content increased (P = 0.008). The smallest hierarchical follicle numbers of XH3 and MB1 rapeseed were lower than that of the control group (P = 0.009). After 4 wk withdrawal, the egg weight, egg mass, and FCR did not recover (P = 0.011, P = 0.033, P = 0.024, respectively). In conclusion, 11.5% rapeseed decreased egg production performance which might be caused by decreasing hormone levels, and high Gls and EA rapeseed had a lower performance than low Gls and EA rapeseed.

Maternal inulin intake has been shown to alleviate oxidative stress in piglets, but the role of bile acids (BAs) in this process remains unknown. This study aimed to investigate the roles of gut microbiota and BAs metabolism in the amelioration of intestinal oxidative stress in piglets through a maternal inulin diet. A total of 40 sows were allocated into two dietary treatments from day 85 of gestation until the end of lactation: CON (control diet) and INU (diet with 2% wheat bran replaced by inulin). An oxidative model was further established on the intestinal porcine epithelial cell-jejunum 2 cell line (IPEC-J2) to examine the effect of bacterial BAs on intestinal oxidative stress. Results showed that the maternal inulin diet promoted the average daily gain of piglets during suckling and reduced diarrhea rate during weaning (P = 0.026 and P = 0.005, respectively). Piglets from the INU group had lower serum levels of reactive oxygen species (P = 0.021), malondialdehyde (P = 0.045), along with higher serum levels of glutathione peroxidase (P = 0.027), catalase (P = 0.043), and total superoxide dismutase (P = 0.097). Compared to the CON group, maternal inulin intake increased fecal ursodeoxycholic acid (UDCA) by 10.84%, hyodeoxycholic acid (HDCA) by 250.64% (P = 0.026), and lithocholic acid (LCA) by 16.41% (P = 0.048) in piglets. Moreover, the fecal abundance of Ruminococcus and Christensenellaceae_R-7_group increased by 167.08% and 75.47% in INU piglets (P = 0.046 and P = 0.037, respectively). Furthermore, the in vitro study using IPEC-J2 cells demonstrated that UDCA, LCA, and HDCA attenuated intestinal oxidative stress by mediating kelch-1ike ECH-associated protein 1/nuclear factor E2-related factor 2 signaling. In conclusion, our results suggested that maternal dietary inulin intake during late gestation and lactation alleviates intestinal oxidative stress of piglets by regulating gut microbiota and BA metabolism.

Improving the nutrient utilization efficiency of ruminants is of utmost significance for both economic and environmental benefits. Optimizing dietary protein levels represents a key nutritional strategy to enhance ruminant growth performance and reduce nitrogen emissions. In a 63-day experiment, 24 healthy Hulunbuir lambs (initial weight 17.1 ± 2.0 kg, 2.5 months old) were subjected to three treatments: a low-protein diet (LP; crude protein of 78.4 g/kg dry matter [DM]), a medium-protein diet (MP; crude protein of 112.0 g/kg DM), and a high-protein diet (HP; crude protein of 145.6 g/kg DM), with 8 lambs in each treatment (4 males and 4 females). Lambs in the MP treatment presented greater daily weight gain and feed conversion ratio than those in the HP treatment (P < 0.05, quadratically). Compared with the LP treatment, the MP treatment resulted in greater crude protein digestibility (P < 0.001, quadratically) and acid detergent fiber digestibility (P = 0.022, quadratically). In the serum, the urea nitrogen level increased quadratically with increasing dietary protein levels (P < 0.001), while the LP treatment exerted the highest concentrations of glutamate, glycine, alanine, and histidine (P < 0.05, quadratically). The ammonia nitrogen concentrations in the rumen and colon increased quadratically with increase in dietary protein levels (P < 0.05). The HP treatment increased the molar concentrations of isobutyrate and isovalerate in the rumen and colon (P < 0.05, quadratically). In contrast, the LP treatment decreased the molar proportion of acetate (P = 0.007, quadratically) and increased the molar proportion of butyrate (P < 0.001, quadratically) in the colon. The microbial diversity and structure were significantly altered by dietary protein level intervention across all gastrointestinal regions. The rumen of the MP treatment was enriched with fiber-degrading bacteria Fibrobacter_succeinogenes and starch-degrading bacteria Selenomonas_ruminantium. The colon in the LP treatment harbored microbial biomarkers including Escherichia spp. and Lactobacillus amylovorus, and the colon in the MP treatment was characterized by the enrichment of Solibacillus_cecembensis. These findings suggest that the MP diet with a crude protein content of 112.0 g/kg DM improved the growth performance and nutrient efficiency of lambs, which was achieved via the involvement of the gastrointestinal microbiota.

Feedstuffs derived from canola, predominantly canola meals plus whole, "full-fat" canola seed, and even canola protein isolates and/or concentrates, have the potential to decrease soybean meal inclusions in diets for broiler chickens. The protein content of soybean meal exceeds that of canola meal; however, canola meal contains more methionine and cysteine in absolute and relative terms. The purpose of this review is to explore this potential as Australian chicken-meat production is uniquely positioned to take advantage of this opportunity to the extent that it can be realised. Australia harvests ample quantities of canola, the bulk of which is exported as seed; alternatively, soybean production is very limited; therefore, large quantities of soybean meal are imported as the principal source of dietary protein for broiler chickens. This importation of soybean meal is not sustainable; however, canola meal inclusions in broiler diets do not usually exceed 100 g/kg. Regression equations derived from 15 recent studies indicate that dietary inclusions of 150 g/kg solvent-extracted canola meal would compromise weight gain by 4.04% and feed conversion ratio (FCR) by 4.72%. The foremost factors driving these depressions in canola meal are probably (1) high fibre contents coupled with low energy densities and (2) the presence of glucosinolates, which may be converted into toxic metabolites including thiocyanates. Moreover, regression equations from nine studies suggest that calculated dietary glucosinolate concentrations of 2.00 μmol/g would compromise weight gain by 5.72% and FCR by 6.56%. The nutritive value of canola meal could be enhanced by improvements in canola breeding programs, processing methods in canola meal production, and dietary formulations including judicious application of exogenous enzymes. Consideration is given to these aspects in this review as any improvements would increase the extent to which canola meal can feasibly replace soybean meal in broiler diets. An additional pathway to decrease the reliance on soybean meal could be the adoption of reduced-crude protein (CP) diets containing canola meal. The combined strategy of canola meal replacing soybean meal in reduced-CP diets, if successful, would tangibly decrease soybean meal requirements in global chicken-meat production.

Maternal proline (Pro) supplementation enhances fetal survival and placental development in mice. However, the effect of Pro on fetal and placental development in gilts remains to be investigated, particularly in the context of obesity-induced impaired pregnancy. Here, we investigated the effect of dietary Pro on fetal and placental development in obese gilts. Exp.1: On day 60 of gestation, 48 gilts with similar delivery times were selected and followed up until delivery to determine the relationship between maternal obesity, litter performance, and Pro abundance in term placentae. The results showed that impaired reproductive performance was associated with body condition parameters and inadequate placental Pro availability of gilts. Exp. 2: A total of 114 gilts were then used in a 2 × 3 factorial design to investigate the interaction between body condition (factor I: normal or obese gilts) and dietary Pro levels (factor II: low [0.89%, L-Pro], medium [1.39%, M-Pro], and high [1.89%, H-Pro]) on farrowing performance and placental angiogenesis. This resulted in six treatment combinations: normal-L-Pro, obese-L-Pro, normal-M-Pro, obese-M-Pro, normal-H-Pro, and obese-H-Pro. The effective number of replicates per group was 17, 21, 19, 21, 18, and 18, respectively (1 gilt per replicate). The results showed that increasing Pro intake increased piglet birth weight (P = 0.001), litter weight (P < 0.001), placental efficiency (P = 0.036) and placental vascular density (P < 0.001), and decreased the number of mummified fetuses (P = 0.001), the rate of low-birth-weight piglets (P = 0.005), and the rate of invalid piglets (P = 0.029). Interaction effects were observed between body condition and dietary Pro levels on piglet birth weight (P = 0.046), within-litter birth weight variation (P = 0.012), and placental vascular density (P = 0.007). Moreover, the beneficial effect of Pro on farrowing performance may be related to the improvement of sirtuin 1-superoxide dismutase 2-mitochondrial reactive oxygen species axis homeostasis and angiogenesis in the placenta. Our results suggest that gestation diets need to provide adequate Pro to meet the needs of fetal and placental development, particularly in obese gilts.