During the growing period, the gastrointestinal tract of layer pullets is not yet well developed and may be susceptible to dietary energy level. The energy level and composition might impact the intestinal energy metabolism of layer pullets. To test this hypothesis, a total of 480 "Jing Tint 6" layer pullets were used in an 8-week study and allocated to 4 groups, each consisting of 8 replicates, with 15 birds per replicate. Pullets were treated with low or high starch:fat ratios (LS, 10:1; HS, 20:1) in a 2 × 2 factorial arrangement with regular energy (RE, 11.85 and 11.68 MJ/kg for birds from 6 to 10 weeks of age and 11-14 weeks of age, respectively) or low energy (LE, 0.55 MJ/kg lower than RE) levels. A significant interaction (P < 0.05) showed that HS increased glandular stomach weight and the jejunal villus length to crypt depth ratio (VCR) in LE diets, but decreased these parameters in RE diets. Dietary energy reduction impaired energy metabolism in the ileum (P < 0.05) mainly via decreasing the gene expression of enzymes involved in the tricarboxylic acid (TCA) cycle (α-ketoglutarate dehydrogenase complex [α-KGDH]; isocitrate dehydrogenase (NAD (+) [IDH] catalytic; citrate synthase [CS]) and adenosine triphosphate (ATP) synthesis, reducing contents of phosphoenolpyruvate (PEP) and adenylate energy charges (AEC) and down-regulating the adenosine monophosphate-activated protein kinase (AMPK) pathway. HS stimulated AMPKα phosphorylation, increased protein abundance of peroxisome proliferator activated-receptor gamma coactivator 1α (PGC1α) and improved contents of amino acids (aspartate, glutamate, glutamine, alanine and threonine) and malate in the ileum regardless of energy levels (P < 0.05). By an interaction (P < 0.05), the transition from LS to HS diets up-regulated ileal gene expression of AMPKα1 and decreased content of adenosine monophosphate (AMP), accompanied by higher AEC but only in birds fed with LE diets. Collectively, these results suggest that low energy feeding may not be enough for maintaining intestinal energy homeostasis in layer pullets and emphasizes the importance of a relatively high starch:fat ratio in restoring energy metabolism in the ileum.

L-arginine (L-Arg) is one of the most widely used amino acids in dietary and pharmacological products. However, the evidence on its usefulness and dose limitations, especially in diabetics is still controversial.

To investigate the effects of chronic administration of different doses of L-Arg on the cardiac muscle of type 2 diabetic rats.

Of 96 male rats were divided into 8 groups as follows (n = 12): Control, 0.5 g/kg L-Arg, 1 g/kg L-Arg, 1.5 g/kg L-Arg, diabetic, diabetic + 0.5 g/kg L-Arg, diabetic + 1 g/kg L-Arg, and diabetic + 1.5 g/kg L-Arg; whereas L-Arg was orally administered for 3 months to all treated groups.

L-Arg produced a moderate upregulation of blood glucose levels to normal rats, but when given to diabetics a significant upregulation was observed, associated with increased nitric oxide, inflammatory cytokines, and malonaldehyde levels in diabetic rats treated with 1 g/kg L-Arg and 1.5 g/kg L-Arg. A substantial decrease in the antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione concentrations, and Nrf-2 tissue depletion were observed at 1 g/kg and 1.5 g/kg L-Arg diabetic treated groups, associated with myocardial injury, fibrosis, α-smooth muscle actin upregulation, and disruption of desmin cardiac myofilaments, and these effects were not noticeable at normal treated groups. On the other hand, L-Arg could significantly improve the lipid profile of diabetic rats and decrease their body weights.

L-Arg dose of 1 g/kg or more can exacerbates the diabetes injurious effects on the myocardium, while 0.5 g/kg dose can improve the lipid profile and decrease the body weight.

Intrauterine growth retardation (IUGR) in piglets is associated with a high rate of morbidity and mortality after birth due to gut dysfunction, and the underlying mechanisms remain poorly understood. This study selected six pairs of IUGR newborn male piglets and normal birth weight newborn piglets (Large White × Landrace) to investigate differences in intestinal structure and digestive functions, intestinal ERS and apoptosis, intestinal barrier function, and inflammatory response. The results showed that IUGR significantly reduced the jejunal villi height (p < 0.05) and the ratio of villus-height-to-crypt-depth (p = 0.05) in neonatal piglets. Additionally, the microvilli in the jejunum of IUGR neonatal piglets were shorter than those in normal-weight piglets, and swelling of the mitochondria and expansion of the endoplasmic reticulum were observed. IUGR also significantly reduced serum glucose and lactase levels (p < 0.05) while significantly increasing mRNA levels of jejunal IRE1α, EIF2α, CHOP, Bax, Caspase9, Mucin2, Claudin-1, Occludin, ZO-1, Bcl-2, IL-6, and IFN-γ (p < 0.05), as well as GRP78 protein levels in neonatal piglets (p < 0.05). These findings suggest that IUGR impairs intestinal structure and barrier function in newborn piglets by enhancing intestinal inflammatory responses, activating intestinal ERS and the signaling pathways related to the unfolded protein response, thereby inducing ERS-related apoptosis.

Improving the efficiency and production of grazing ruminants to support food and fiber production, while reducing the environmental footprint and meeting the welfare needs of the animals, is important for sustainable livestock production systems. Development of new technologies that can improve the efficiency of nitrogen (N) utilization in ruminants, and that are effective and safe, has important implications for ruminant livestock production. N-carbomoylglutamate (NCG) is a functional micronutrient that stimulates endogenous synthesis of arginine, which can improve survival, growth, lactation, reproductive performance, and feed efficiency in mammals. There is a growing body of evidence to support the potential of dietary NCG supplementation to improve the productive capacity and N utilization efficiency of ruminants. This review summarizes the current literature on the effects of dietary supplementation with NCG in ruminants and impacts on production and potential to reduce the environmental footprint of farmed ruminant livestock. The current literature highlights the potential for commercial application in ruminant livestock to improve productivity and N utilization efficiency.

Introduction: Ammonia has been of concern for its high toxicity to animals. N-carbamylglutamate (NCG) can reduce blood ammonia levels in mammals, but studies on ammonia tolerance in fish are insufficient. Methods: Juvenile yellow catfish were fed two levels of NCG (0.00% and 0.05%) for 84 days under three ammonia levels (0.00, 0.08, and 0.16 mg/L NH₃). Results and Discussion: The results showed that survival rate (SUR), final body weight (FBW), weight gain (WG), and serum total protein (TP), triglycerides (TG), glucose (Glu), ornithine (Orn), citrulline (Cit) contents, and liver superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), arginase (ARG), ornithine transcarbamylase (OTC) activities decreased with the increase of ammonia levels, on the contrary, feed conversion ratio (FCR), hepatosomatic index (HSI), and serum ammonia, urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamine (Gln), arginine (Arg) contents, and liver malondialdehyde (MDA), tumor necrosis factor (TNF), interleukin (IL) 1, IL 8 contents, and mRNA expressions of cu/zn sod, cat, gpx, gr, tnf ɑ, il 1, and il 8 were significantly increased. Dietary 0.05% NCG supplementation had higher SUR, FBW, WG, feed intake (FI), whole-body protein, and serum TP, total cholesterol (TC), Glu, citrulline (Cit) contents, and liver SOD, GPx, argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL), inducible nitric oxide synthase (iNOS) activities compared to 0.00% NCG group, but had lower serum ammonia, urea, ALT, AST, Gln, Arg contents, and liver MDA, TNF, IL 1, IL 8 contents, and neuronal nitric oxide synthase activity. At the end of bacterial challenge, cumulative mortality (CM) increased with ammonia levels increased, but serum antibody titer (AT), lysozyme (LYZ) activity, 50% hemolytic complement, immunoglobulin (Ig) contents, respiratory burst (RB), phagocytic indices decreased with ammonia levels increased. CM in 0.05% NCG group was lower than that in 0.00% NCG group, but serum AT, LYZ activity, Ig content, RB in 0.05% NCG group were significantly higher. The correlation analysis found that iNOS was positively correlated with ASS activity. This study indicates that dietary NCG supplementation can improve the ammonia tolerance of yellow catfish, and ASS may also be the target of NCG to activate the urea cycle.