The microbiome has emerged as a new player on behavior, physiology and stress because of its significant effects on the brain-gut axis. The aim of this study was to increase our understanding of brain-gut function in dairy cows. We investigated the effects of a heat-stress (HS) environment and individual differences of heat sensitivity (IH) on bovine physiological characteristics and microbial composition. Results indicate that both HS and IH increased rectal temperature (RT) (P < 0.05). An HS environment increased plasma, as well as milk cortisol and cytokines in plasma; however, it decreased plasma, and milk oxytocin, triiodothyronine, and thyroxine (P < 0.05) levels. Exposure to an HS environment reduced the diversity of the fecal microbial population, and resulted in a higher expression of diseases, the environmental adaptation pathway, and the immune related pathway, whereas it lowered the expression of metabolic pathways (P < 0.05). High heat sensitive cows have upregulated metabolisms, environmental adaptation and cellular process pathways, and a downregulated neurodegenerative disease pathway (P < 0.05). Thus, we conclude that exposure to an HS environment modulates physiological characteristics, which may interplay with microbial activity, and in turn, alter the circulation levels of cytokines, implicating the role of the brain-gut axis in dairy cows. The HS environment affected physiological characteristics, cytokine levels, and microbial composition, but IH influenced RT and fecal microbial functions.

This study aimed to evaluate the effect of hydroxy-selenomethionine (HMSeBA), a novel organic selenium (Se) source, on milk performance, antioxidative status, and Se concentrations in the milk and plasma of mid-lactation dairy cows compared with that of sodium selenite (SS). Fifty mid-lactation dairy cows with similar days in milk, milk yield, and parity received the same basal diet containing 0.06 mg of Se/kg of DM. They were assigned to 1 of 5 treatments according to a randomized complete block design: negative control (without Se supplementation), SS supplementation (0.3 mg of Se/kg of DM; SS-0.3) or HMSeBA supplementation (0.1, 0.3, or 0.5 mg of Se/kg of DM: SO-0.1, SO-0.3, and SO-0.5, respectively). The experiment lasted for 10 wk, including a pretrial period of 2 wk. The results indicated that neither Se supplementation nor Se source affected dry matter intake, milk yield, milk composition, or blood biochemical parameters, except for milk fat percentage. Simultaneously, milk fat percentage and milk fat yield increased linearly as the quantity of HMSeBA supplementation was increased. Production of 4% FCM and ECM was elevated linearly as dietary HMSeBA increased. The SO-0.3 group showed higher serum activity of glutathione peroxidase, total antioxidant capacity, and superoxide dismutase than the SS-0.3 group, but malondialdehyde content was not affected by Se source. Furthermore, HMSeBA supplementation linearly increased the activities of serum glutathione peroxidase and superoxide dismutase, but decreased malondialdehyde content. Compared with the SS-0.3 group, the SO-0.3 group showed augmented concentrations of total Se in milk and plasma, and total Se milk-to-plasma concentration ratio. In addition, increasing doses of HMSeBA linearly increased the concentrations of total Se in the milk and plasma. This study demonstrates that HMSeBA improves antioxidant status and increases milk and plasma Se concentrations more effectively than SS, indicating that HMSeBA could replace SS as an effective organic Se source for lactating dairy cows.

The aim of this study was to evaluate the dosedependent effects of a hydroxy-analog of selenomethionine (HMSeBA) on rumen fermentation, apparent nutrient digestibility, and total selenium absorption in mid-lactation dairy cows, and to compare the effects with those of sodium selenite (SS). Fifty mid-lactation dairy cows with similar milk yields, days in milk, and parity were randomly assigned to 1 of 5 treatments according to a randomized complete block design. The cows were fed a basal diet containing 0.06 mg/kg dry matter (DM) of Se (control) or the same basal diet supplemented with SS, yielding 0.3 mg of Se/kg of DM (SS-0.3), or HMSeBA, yielding 0.1, 0.3, or 0.5 mg of Se/ kg of DM (SO-0.1, SO-0.3, and SO-0.5, respectively), during the experimental period. The final content of Se in control, SS-0.3, SO-0.1, SO-0.3, and SO-0.5 was 0.06, 0.34, 0.15, 0.33, and 0.52 mg of Se/kg of DM.The experiment lasted for 10 wk, with a pretrial period of 2 wk. Supplementation with HMSeBA altered rumen fermentation by linearly increasing total volatile fatty acids and the molar proportions of propionate and butyrate but decreasing rumen pH, ammonia content, and the ratio of acetate to propionate. Compared with SS, HMSeBA enhanced the molar proportion of propionate in the rumen and the apparent digestibility of crude protein, neutral detergent fiber, acid detergent fiber, and selenium. We demonstrated that HMSeBA promoted rumen fermentation, apparent nutrient digestibility, and selenium absorption, implying that HMSeBA has a greater apparent absorption than SS.

Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight (BW) and pectoral muscle growth of broilers. In this experiment, we further investigated the morphological and molecular basis of this phenomenon. Fertile broiler eggs (Arbor Acres, n = 880) were pre-weighed and randomly assigned to 1 of the 2 incubation treatment groups: (1) dark condition (control group), and (2) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. The dark condition was set as a commercial control from day 1 until hatching. After hatch, 120 male 1-day-old chicks from each group were housed under incandescent white light with an intensity of 30 lx at bird-head level. No effects of light stimuli during embryogenesis on hatching time, hatchability, hatching weight and bird mortality during the feeding trial period were observed in the present study. Compared with the dark condition, the BW, pectoral muscle weight and myofiber cross-sectional areas were significantly greater on 7-day-old chicks incubated under green light. Green light also increased the satellite cell mitotic activity of pectoral muscle on 1-and 3-day-old birds. In addition, green light upregulated MyoD, myogenin and myostatin mRNA expression in late embryos and/ or newly hatched chicks. These data suggest that stimulation with monochromatic green light during incubation promote muscle growth by enhancing proliferation and differentiation of satellite cells in late embryonic and newly hatched stages. Higher expression of myostatin may ultimately help prevent excessive proliferation and differentiation of satellite cells in birds incubated under green light.

No abstract

An 8‐week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio (CHO: L) on growth, feed utilization, body composition and digestive enzyme activities of golden pompano, Trachinotus ovatus. Five iso‐nitrogenous (450 g/kg protein) and iso‐energetic (19 MJ/kg gross energy) diets with varying CHO: L ratios of 0.68, 1.02, 1.62, 2.61 and 4.35, respectively, were fed to triplicate groups of 30 fish (average 13.8 ± 0.1 g). Results showed that dietary CHO: L ratios did not show any significant influence on survival of golden pompano (p > .05) but significantly affected its growth performance and feed utilization (p < .05). Fish fed diets with CHO: L ratios at 1.62 and 2.61 exhibited the highest final body weight, weight gain ratio, specific growth rate, feed efficiency ratio and protein efficiency ratio. Fish body lipid and liver glycogen contents were also significantly influenced by CHO: L ratio (p < .05). Hepatic amylase activity increased firstly and then decreased as the dietary CHO: L ratio increased, while lipases activity decreased with increasing dietary CHO:L level. The regression model analysis showed that the most suitable dietary CHO: L ratio (protein 450 g/kg) to reach the highest weight gain ratio is 2.38.

No abstract

Pulmonary vascular remodelling, mainly characterized by arterial medial thickening, is an important pathological feature of broiler ascites syndrome (AS). Since vascular smooth muscle cells (VSMC) form the major cellular component of arterial medial layer, we speculate that VSMC proliferation is one of the causes of pulmonary arterial medial thickening in ascitic broilers. Hence, the present study was designed to investigate the role of VSMC proliferation in pulmonary vascular remodelling in development of AS induced by low ambient temperature. Broilers in control group (22 +/- 1.5 degrees C) and low temperature group (11 +/- 2 degrees C) were sampled every week at 15-50 days of age. Proliferative indexes of VSMC in pulmonary arteries were assessed with proliferating cell nuclear antigen, and the relative medial thickness (RMT) and relative wall area (RWA), as indexes of pulmonary vascular remodelling, were examined by computer-image analysing system. The results showed that the high incidence (18.75%) of AS was induced by low temperature, and a significantly increased VSMC proliferation was observed in pulmonary arteries in the low temperature group at 22-50 days of age (P < 0.05). In addition, RMT and RWA in pulmonary arteries were significantly elevated in the low temperature group from 36 days of age (P < 0.05), indicating that pulmonary vascular remodelling occurred following VSMC proliferation in AS. Our data suggest that proliferation of VSMC may facilitate pulmonary vascular remodelling and have a pivotal role in AS induced by low ambient temperature.