Zinc glycinate alleviates LPS-induced inflammation and intestinal barrier disruption in chicken embryos by regulating zinc homeostasis and TLR4/NF-κB pathway.

The effect of an immune challenge induced by a lipopolysaccharide (LPS) exposure on systemic zinc homeostasis and the modulation of zinc glycinate (Zn-Gly) was investigated using a chicken embryo model. 160 Arbor Acres broiler fertilized eggs were randomly divided into 4 groups: CON (control group, injected with saline), LPS (LPS group, injected with 32 µg of LPS saline solution), Zn-Gly (zinc glycinate group, injected with 80 µg of zinc glycinate saline solution) and Zn-Gly+LPS (zinc glycinate and LPS group, injected with the same content of zinc glycinate and LPS saline solution). Each treatment consisted of eight replicates of five eggs each. An in ovo feeding procedure was performed at 17.5 embryonic day and samples were collected after 12 hours. The results showed that Zn-Gly attenuated the effects of LPS challenge-induced upregulation of pro-inflammatory factor interleukin 1ß (IL-1ß) level (P =0.003). The LPS challenge mediated zinc transporter proteins and metallothionein (MT) to regulate systemic zinc homeostasis, with increased expression of the jejunum zinc export gene zinc transporter protein 1 (ZnT-1) and elevated expression of the import genes divalent metal transporter 1 (DMT1), Zrt- and Irt-like protein 3 (Zip3), Zip8 and Zip14 (P < 0.05). A similar trend could be observed for the zinc transporter genes in the liver, which for ZnT-1 mitigated by Zn-Gly supplementation (P =0.01). Liver MT gene expression was downregulated in response to the LPS challenge (P =0.004). These alterations caused by LPS resulted in decreased serum and liver zinc levels and increased small intestinal, muscle and tibial zinc levels. Zn-Gly reversed the elevated expression of the liver zinc finger protein A20 induced by the LPS challenge (P =0.025), while Zn-Gly reduced the gene expression of the pro-inflammatory factors IL-1ß and IL-6, decreased toll-like receptor 4 (TLR4) and nuclear factor kappa-B p65 (NF-κB p65) (P < 0.05). Zn-Gly also alleviated the LPS-induced downregulation of the intestinal barrier gene Claudin-1. Thus, LPS exposure prompted the mobilization of zinc transporter proteins and MT to perform the remodeling of systemic zinc homeostasis, Zn-Gly participated in the regulation of zinc homeostasis and inhibited the production of pro-inflammatory factors through the TLR4/NF-κB pathway, attenuating the inflammatory response and intestinal barrier damage caused by an immune challenge.

Dietary 25-hydroxy-cholecalciferol and additional vitamin E improve bone development and antioxidant capacity in high-density stocking broilers.

This study aimed to investigate the effects of diets supplemented with 25-hydroxycholecalciferol [25-(OH)D3] and additional vitamin E on growth performance, antioxidant capacity, bone development, and carcass characteristics at different stocking densities on commercial broiler farms. A total of 118,800 one-day-old Arbor Acres broilers were assigned to a 2 × 2 factorial treatment consisting of two dietary vitamin levels (5,500 IU vitamin D3 and 60 IU vitamin E: normal diet, using half 25-(OH)D3 as a source of vitamin D3 and an additional 60 IU of vitamin E: 25-(OH)D3+VE diet) and two stocking densities (high density of 20 chickens/m2: HD and 16 chickens/m2: LD). The experiment lasted for 42 d. The results showed that high-density stocking negatively affected the growth performance of broilers during the first four weeks, whereas the vitamin diet treatment significantly improved the feed conversion ratios (FCR) during the last 2 wk. Vitamin diets increased catalase at 14 and 42 d, and the glutathione peroxidase (GSH-px) levels at 42 d in high-density-stocked broilers. The interaction showed that serum vitamin E levels were significantly improved at 28 d of age in high-density-stocked broilers as a result of the vitamin diets. Stocking density and dietary treatments were found to significantly affect bone development, with the vitamin diet significantly increasing metatarsal length and femoral bone strength in broilers from high-density stocking density at 28 d of age. High stocking density increased the proportion of leg muscles and meat yield per square meter. In general, 25-(OH)D3 and additional vitamin E suppressed oxidative stress and ameliorated the negative effects of high-density stocking on bone development in a commercial chicken farm setting. Vitamin diets improved the FCR of broilers, while high-density stocking resulted in better economic outcomes.

High-density stocking is often associated with animal welfare risks in broilers, mainly in terms of oxidative stress and bone development. Nevertheless, farming at too low a density remains for the most part economically unviable. Modulation of antioxidant capacity and bone development by nutritional strategies in high-density-farmed broilers has proven an effective tool in developing countries. Therefore, the present study investigated the effects of applying diets with a higher biological potency of vitamin D3 25-hydroxycholecalciferol [25-(OH)D3] and a higher concentration of vitamin E on broiler production performance, antioxidant capacity and meat production performance at different densities of stocking under commercial farming conditions. The results indicated that the vitamin dietary treatments suppressed oxidative stress and ameliorated the negative effects of high-density farming on bone development.

Dietary sodium butyrate improves female broiler breeder performance and offspring immune function by enhancing maternal intestinal barrier and microbiota.

This study aimed to investigate the effects of dietary sodium butyrate (SB) supplementation on the reproductive performance of female broiler breeders under intensive rearing conditions and to analyze antioxidant capacity, immune function, and intestinal barrier function of the female breeders and their offspring. A total of 96,000 40-wk-old Ross308 female broiler breeders were divided into the control (CON) and SB groups, each with 6 replicates of 8,000 birds. Each house with similar production performance characteristics was considered a replicate. The experiment lasted for 20 wk, whereupon sampling took place. Results showed that SB improved the egg production performance, egg quality of broiler breeders, and hatchability (P < 0.05). Maternal supplementation with SB substantially increased serum immunoglobulin A levels in broiler breeders and offspring (both P = 0.04) and offspring immunoglobulin G (P < 0.001). The levels of interleukin-1ß (P < 0.001) and interleukin-4 (P = 0.03) in the offspring were downregulated, while the total superoxide dismutase in the offspring and the eggs increased (P < 0.05). The serum biochemical components in breeders and offspring were altered by SB, as evidenced by the reduction in triglycerides, total cholesterol, and high- and low-density lipoproteins (P < 0.05). The intestinal morphology of broiler breeders and offspring also improved by the SB with the decreasing the jejunal crypt depth (P = 0.04) and increasing villus height in offspring (P = 0.03). Maternal jejunal and ileal intestinal barrier-related genes were also shown to be significantly affected by SB. Furthermore, SB altered the microbial diversity in maternal cecal contents, thus increasing the abundance of Lachnospiraceae (P = 0.004) and Ruminococcaceae (P = 0.03). Dietary SB enhanced the reproductive performance and egg quality of broiler breeders and improved the antioxidant capacity and immune function of broiler breeders and offspring, with the benefits potentially arising from the regulation of the maternal intestinal barrier and gut microbiota by SB.

Dietary Qi-Weng-Huangbo powder enhances growth performance, diarrhoea and immune function of weaned piglets by modulating gut health and microbial profiles.

Introduction: The evolution of nutritional strategies to improve the gut health and microbiota profiles of early-weaned piglets is essential to reduce diarrhoea caused by weaning stress. Therefore, the aim of this study was to determine the effects of dietary supplementation of Qi-Weng-Huangbo powder, a traditional herbal medicine consisting of a mixture of Pulsatilla chinensis, Chinese Schneid and Astragalus extracts (PCE), on the growth performance, diarrhoea rate, immune function and intestinal health of weaned piglets. Methods: 162 piglets were randomly assigned to the CON group (no PCE added), the PCEL group (300 mg/kg PCE) and the PCEH group (500 mg/kg PCE) at the end of the third week post farrowing. There were 9 replicates of each group with 6 pigs per replicate. The experiment lasted for 28 days and sampling was performed on the final day. Results: The results showed that the PCE diet increased the average daily gain (ADG) and final body weight (BW) compared to the CON group. Both supplemented doses of PCE reduced the faecal scores of piglets, and the diarrhoea rate in the PCEL group was significantly lower than that in the CON group. The application of PCE diets promoted the development of the spleen in piglets and up-regulated serum immunoglobulin concentrations to enhance immune function, which was also reflected in the down-regulated gene expression of the colonic TLR/MyD88/NF-κB pathway. Supplementation with PCE improved intestinal morphology, and all doses of PCE significantly increased villus height (VH) in the ileum, whereas colonic crypt depth (CD) was significantly lower in the PCEH group than in the CON group. The PCEH diet significantly increased the levels of valeric and isovaleric acid in the colon content. Dietary PCEH also improved the colonic microbial community profile, reflected by a significant increase in Shannon's index compared with CON group. The abundance of Veillonellaceae and Rhodospirillales was significantly increased in the PCEH group at the family level. Discussion: In conclusion, dietary PCE reduced diarrhoea rates, improved growth performance and enhanced immune function in weaned piglets. These improvements were potentially supported by altered ileum and colonic morphology, elevated colonic VFA levels, and modulation of colonic microbial profiles.

Effect of dexamethasone on gene expression of cannabinoid receptor type 1 and adenosine monophosphate-activated protein kinase in the hypothalamus of broilers (Gallus domesticus).

Hypothalamic neural circuits play a critical role in integrating peripheral signals and conveying information about energy and nutrient status. We detected cannabinoid receptor type 1 (CB1) distribution in the hypothalamus, liver, duodenum, jejunum, and ileum among 7- and 35-day-old broilers. The effects of dexamethasone (DEX) on CB1 gene expression were evaluated by in vitro and in vivo experiments on glucocorticoid receptor (GR) and adenosine monophosphate-activated protein kinase (AMPK) in the hypothalamus of broilers. In vitro, hypothalamic cells from 17-day-old broiler embryos were incubated with either 0.1% dimethyl sulfoxide or DEX (100 nmol/mL) for 1 h. In the in vivo study, 28-day-old broilers were injected with DEX for 24 h or 72 h. Results showed that CB1 was mainly expressed in the hypothalamus, and 72 h DEX treatment increased the expression. One-day treatment of broilers with DEX did not change the hypothalamic CB1 gene expression. Moreover, DEX treatment for 24 h and 72 h increased the mRNA level of hypothalamic AMPKα2 and GR. However, no differences were observed on the gene expression of CB1, GR, and AMPKα2 in hypothalamic cells with DEX-treated for 1 h. In conclusion, CB1 is mainly expressed in the hypothalamus of broilers; 72-h DEX exposure can regulate the CB1 system and AMPK signaling pathway of the broiler hypothalamus.

The AMPK-mTOR signaling pathway is involved in regulation of food intake in the hypothalamus of stressed chickens.

Glucocorticoids (GCs) can stimulate the appetite and AMPK in broilers. The activation of hypothalamic mTOR has been proposed as an important anorexigenic signal. However, inhibitory effect of AMPK activity on appetite and AMPK downstream signaling pathway under stress has not been reported. In this study, we performed an intracerebroventricular (icv) injection of compound C, an AMPK inhibitor, in GC-treated birds to explore the regulatory mechanism on appetite and AMPK downstream signaling pathway. A total of 48 7-day-old broilers, which had received an icv cannula, were randomly subjected to one of two treatments: subcutaneous injection of dexamethasone (DEX) or saline. After 3 days of continuous DEX injection, chicks of each group received an icv injection with either compound C (6 µg/2 µL) or vehicle (dimethyl sulfoxide, 2 µL). The results showed that body weight gain was reduced by the DEX treatment. Compared with the control, icv injection of compound C reduced feed intake at 0.5-1.5 h. In the DEX-treated group, the inhibitory effect of compound C on appetite remained apparent at 0.5-1 h. The DEX treatment increased the gene expression of liver kinase B1 (LKB1), neuropeptide Y (NPY), and decreased p-mTOR protein level. In stressed broilers, inhibition of AMPK relieved the decreased mTOR activity. A significant interaction was noted in DEX and compound C on protein expression of phospho-AMPK. Taken together, in stressed broilers, the central injection of compound C could inhibit central AMPK activity and reduce appetite, in which the AMPK/mTOR signaling pathway might be involved.