Dietary Betaine improves the intestinal health and growth performance of heat-stressed growing rabbits in summer.

The main objective of this study is to explore how various amounts of Bet affect growth performance, nutritional digestibility, and intestinal health of growing rabbits under high-temperature environment in summer. A total of 150 healthy 35-d-old weaned QiXing meat rabbits (Germany White rabbit × Sichuan White rabbit) were individually assigned to five treatments, each with 30 replicates and one rabbit per replicate. The control group was fed with basal diet, while the experimental group received a basal diet supplemented with 0.75, 1.0, 1.5, and 2.0 g Bet/kg diet, respectively. During the whole experimental stage, all animals can eat and drink freely, and they were kept in the rabbit house with an average daily temperature of 30.11 ±â€…0.5 ℃ and a relative humidity of 71.02 ±â€…5.07%. The results showed that dietary supplementation with 1.5 g/kg Bet increased average daily gain and decreased feed to gain ratio from days 1 to 42 as compared to the control group (P < 0.05), adding 0.75, 1.0, 1.5, and 2.0 g/kg Bet increased average daily gain and average daily feed intake from days 22 to 42 (P < 0.05), and increased the nutritional digestibility of acid detergent fiber (P < 0.05). Furthermore, dietary supplementation with 1.0, 1.5, and 2.0 g/kg Bet reduced d-lactate content and diamine oxidase activity in the serum (P < 0.05). Compared to the control group, supplementation of 0.75 and 1.5 g/kg Bet improved glutathione peroxidase activities in the duodenum and ileum, adding 0.75, 1.0, 1.5, and 2.0 g/kg Bet decreased malonaldehyde content in the duodenum and jejunum (P < 0.05). Moreover, the supplement of 1.5 and 2.0 g/kg Bet upregulated JAM-2 and IL-10 levels in the jejunum (P < 0.05). In conclusion, supplementation with Bet in the diet improves the growth performance, nutrient digestibility, and intestinal health of growing rabbits under high-temperature environments, and the 1.5 g Bet/kg diet group has the best effect.

Due to the lack of functional sweat glands, rabbits find it difficult to release excess heat under high-temperature conditions, resulting in heat stress. This high-level temperature condition leads to substantial damage to growth performance and intestinal health resulting in significant financial losses for the meat rabbit industry. This study found that adding betaine (Bet) to the diet can improve the growth performance and intestinal barrier integrity of heat-stressed growing rabbits, which may be related to improving intestinal antioxidant capacity and immune status. 1.5 g Bet/kg diet group showed better effects than 0, 0.75, 1.0, and 2.0 g Bet/kg diet groups in improving growth performance and intestinal health of heat-stressed growing rabbits.

2-Hydroxy-4-Methylselenobutanoic Acid Promotes Follicle Development by Antioxidant Pathway.

Selenium (Se) is assumed to promote the follicle development by attenuating oxidative stress. The current study was developed to evaluate the effects of dietary 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) supplementation on the follicle development in vivo and on the function of ovarian granulosa cells (GCs) in vitro. Thirty-six gilts were randomly assigned to fed control diet (CON), Na2SeO3 diet (0.3 mg Se/kg) or HMSeBA diet (0.3 mg Se/kg). The results showed that HMSeBA and Na2SeO3 supplementation both increased the total selenium content in liver and serum compared with control, while HMSeBA increased the total selenium content in liver compared with Na2SeO3 group. HMSeBA tended to increase the total selenium content in ovary compared with control. HMSeBA and Na2SeO3 supplementation both increased the weight of uteri in gilts at the third estrus. Moreover, HMSeBA supplementation down-regulated the gene expression of growth differentiation factor-9 (GDF-9) and bone morpho-genetic protein-15 (BMP-15) in cumulus-oocyte complexes (COCs). HMSeBA supplementation decreased malondialdehyde (MDA) content in serum, liver and ovary, increased activity of T-AOC in liver, TXNRD in ovary and GPX in serum, liver and ovary, while up-regulated the liver GPX2, SOD1 and TXNRD1, ovarian GPX1 gene expression. In vitro, HMSeBA treatment promoted GCs' proliferation and secretion of estradiol (E2). HMSeBA treatment increased the activity of T-AOC, T-SOD, GPX, TXNRD and decreased MDA content in GCs in vitro. Meanwhile, HMSeBA treatment up-regulated SOD2 and GPX1 gene expression in GCs in vitro. In conclusion, HMSeBA supplementation is more conducive to promoting follicle development by antioxidant pathway.

Organic Selenium Increased Gilts Antioxidant Capacity, Immune Function, and Changed Intestinal Microbiota.

Selenium is an indispensable essential micronutrient for humans and animals, and it can affect biological functions by combining into selenoproteins. The purpose of this study was to investigate the effects of 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) on the antioxidant performance, immune function, and intestinal microbiota composition of gilts. From weaning to the 19th day after the second estrus, 36 gilts (Duroc × Landrace × Yorkshire) were assigned to three treatments: control group, sodium selenite group (0.3 mg Se/kg Na2SeO3), and HMSeBA group (0.3 mg Se/kg HMSeBA). Dietary supplementation with HMSeBA improved the gilts tissue selenium content (except in the thymus) and selenoprotein P (SelP1) concentration when compared to the Na2SeO3 or control group. Compared with the control group, the antioxidant enzyme activity in the tissues from gilts in the HMSeBA group was increased, and the concentration of malondialdehyde in the colon had a decreasing trend (p = 0.07). Gilts in the HMSeBA supplemented group had upregulated gene expression of GPX2, GPX4, and SelX in spleen tissue, TrxR1 in thymus; GPX1 and SelX in duodenum, GPX3 and SEPHS2 in jejunum, and GPX1 in the ileum tissues (p < 0.05). In addition, compared with the control group, the expression of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemotactic protein-1 (MCP-1) in the liver, spleen, thymus, duodenum, ileum, and jejunum of gilts in the HMSeBA group were downregulated (p < 0.05), while the expression of interleukin-10 (IL-10) and transforming growth factor-ß (TGF-ß) in the liver, thymus, jejunum, and ileum were upregulated (p < 0.05). Compared with the control group and the Na2SeO3 group, HMSeBA had increased concentration of serum cytokines interleukin-2 (IL-2) and immunoglobulin G (IgG; p < 0.05), increased concentration of intestinal immunoglobulin A (sIgA; p < 0.05), and decreased concentration of serum IL-6 (p < 0.05). Dietary supplementation with HMSeBA also increased the abundance of intestinal bacteria (Ruminococcaceae and Phascolarctobacterium; p < 0.05) and selectively inhibited the abundance of some bacteria (Parabacteroides and Prevotellaceae; p < 0.05). In short, HMSeBA improves the antioxidant performance and immune function of gilts, and changed the structure of the intestinal microflora. And this study provided data support for the application of HMSeBA in gilt and even pig production.

Fecal bacteria and metabolite responses to dietary lysozyme in a sow model from late gestation until lactation.

Lysozyme (LZM) is a natural anti-bacterial protein that is found in the saliva, tears and milk of all mammals including humans. Its anti-bacterial properties result from the ability to cleave bacterial cell walls, causing bacterial death. The current study was conducted to investigate the effects of dietary LZM on fecal microbial composition and variation in metabolites in sow. The addition of LZM decreased the fecal short-chain fatty acids (SCFAs). Zonulin and endotoxin in the serum, and feces, were decreased with lysozyme supplementation. Furthermore, fecal concentrations of lipocalin-2 and the pro-inflammatory cytokine TNF-α were also decreased while the anti-inflammatory cytokine IL-10 was increased by lysozyme supplementation. 16S rRNA gene sequencing of the V3-V4 region suggested that fecal microbial levels changed at different taxonomic levels with the addition of LZM. Representative changes included the reduction of diversity between sows, decreased Bacteroidetes, Actinobacteria, Tenericutes and Spirochaetes during lactation as well as an increase in Lactobacillus. These findings suggest that dietary lysozyme supplementation from late gestation to lactation promote microbial changes, which would potentially be the mechanisms by which maternal metabolites and inflammatory status was altered after LZM supplementation.

Effects of dietary supplementation with lysozyme during late gestation and lactation stage on the performance of sows and their offspring.

This study investigated the effects of supplementing sow diets with lysozyme during the late gestation to lactation stage on the performance of sows and their offspring. Sixty sows (Yorkshire × Landrace, 3 to 6 of parity) at day 85 of gestation were allocated to the following 3 dietary treatments: 1) sows fed a basal diet from late gestation to lactation (control, n = 20), 2) sows fed a basal diet with lysozyme 150 g/t (LZM 150, n = 20), and 3) sows fed a basal diet with lysozyme 300 g/t (LZM 300, n = 20). During the lactation period, sows fed diets containing lysozyme had increased average daily feed intake (ADFI) (P < 0.01) and decreased weaning-to-estrus interval (WEI, P < 0.05), but there were no significant effects on backfat during the trial among treatments. Sows fed lysozyme diets had increased (P < 0.05) serum concentration of total protein (TP) compared with those fed the control diets. Serum immunoglobulin M (IgM) of the sows increased (P < 0.05) on day 1 of lactation, immunoglobulin A (IgA) and interleukin-10 (IL-10) increased (P < 0.05) on day 7 of lactation, and immunoglobulin G (IgG) had a tendency to increase (P = 0.05) during the lactation. Milk concentration of IgA increased (P < 0.05) on day 1 and 7 of lactation and tended to be greater (P = 0.06) on day 21 of lactation. No significant differences among the dietary treatments were observed in placental tissue mRNA expression of interleukin-6 (IL-6), IL-10, tumor necrosis factor-α (TNF-α), polymeric immunoglobulin receptor (pIgR), or the concentrations of IL-6, IL-10, TNF-α, or secretory immunoglobulin A (sIgA). Moreover, there was a decrease (P < 0.05) in stillborn in sows fed lysozyme diets. The diarrhea rate decreased (P < 0.05) and serum concentrations of IgA, IgG, IgM, and IL-10 increased (P < 0.05) in piglets from sows fed the diets containing lysozyme compared with piglets from sows fed the control diet. The serum concentrations of TP increased (P < 0.05), and albumin (ALB) and globulin (GLB) had a tendency to increase (P = 0.08, P = 0.06) in piglets from sows fed the diets containing lysozyme compared with piglets from sows fed the control diet. In conclusion, this study indicates that feeding sows diets supplemented with lysozyme from the late gestation through lactation stage increased sow ADFI during the lactation, shortened the WEI, and improved the maternal and offspring health status as indicated by immunological characteristics and a reduced incidence of diarrhea in piglets.