为明确不同氮源在猪粪废水厌氧发酵过程中氨氮释放规律以及对厌氧发酵的抑制作用，以尿素和氯化铵为外加氮源，以固液分离后的猪粪废水为底物，在中温35 ℃通过批式厌氧发酵，研究不同总氨氮（total ammonia nitrogen, TAN）浓度的外加氮源对猪粪废水厌氧发酵的影响。 结果表明：在猪粪废水厌氧发酵过程中，以尿素为氮源产生的游离氨（free ammonia nitrogen, FAN）、挥发性脂肪酸（volatile fatty acids, VFAs）和pH均明显高于氯化铵，但总氨氮（total ammonia nitrogen, TAN）没有明显区别；以尿素为氮源(TAN≤500 mg·L-1)和以氯化铵为氮源(TAN≤1 500 mg·L-1)均能促进猪粪废水厌氧发酵产甲烷，但超过这一浓度后，均对产甲烷有抑制作用，尿素对猪粪废水厌氧发酵产生抑制的浓度(TAN＞500 mg·L-1)远低于氯化铵(TAN＞1 500 mg·L-1)；相较氯化铵，以尿素为氮源对猪粪废水的厌氧发酵具有更强的氨抑制。本研究为高氨氮抑制厌氧发酵氮源的选择提供了理论依据。
[学术文献] Gastric infusion of short-chain fatty acids can improve intestinal barrier function in weaned piglets 进入全文
Genes & Nutrition
Background: The present study was conducted to investigate the effects of gastric infusion of short-chain fatty acids (SCFA) on gut barrier function in a pig model. In this study, 21 DLY barrows with an average initial body weight of (8.31 ± 0.72) kg were randomly allotted into three treatments: (1) control, (2) infusing low SCFA, S1, (3) infusing high SCFA, S2. The experimental period lasted for 7 days. Results: Gastric infusion of SCFA increased the concentrations of SCFA in serum and digesta, and enhanced the mRNA and protein abundances of SCFA receptors in pig intestine (P < 0.05). Moreover, gastric infusion of SCFA led to alteration of intestinal morphology, elevation of intestinal development-related gene abundances, and decrease of apoptotic cell percentage, as well as reduction of pro-apoptosis gene and protein abundances (P < 0.05). Besides, the jejunal SLC7A1 and ileal DMT1 mRNA abundances in the SCFA infusion groups were higher than those in the control group (P < 0.05). Additionally, gastric infusion of SCFA increased the mRNA abundances of Occludin and Claudin-1 in the duodenum and ileum, enhanced Lactobacillus spp counts in the ileal digesta, decreased the mRNA and protein abundances of IL-1β in the colon, and reduced Escherichia coli count in the ileal digesta (P < 0.05). Conclusions: These data indicated that gastric infusion of SCFA, especially high SCFA concentration, may be beneficial to gut development of piglets via improving gut morphology, decreasing apoptotic cell percentage, and maintaining intestinal barrier function.
[学术文献] Effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation to lactating sows on growth and indicators of stress in the post-weaned pig 进入全文
Dietary n-3 PUFA are precursors for lipid metabolites that reduce inflammation. Two experiments were conducted to test the hypothesis that enriching the sow diet in n-3 PUFA during late gestation and throughout lactation reduces stress and inflammation and promotes growth in weaned pigs. A protected fish oil product (PFO; GromegaTM) was used to enrich the diet in n-3 PUFA. In the initial experiment, time-bred gilts were fed a gestation and lactation diet supplemented with 0 (control; n = 5), 0.25 (n = 4), 0.5 (n = 4) or 1% (n = 5) PFO from 101 ± 2 d of gestation to d 16 of lactation. Adding 1% PFO to the diet increased the n-3:n-6 PUFA ratio in colostrum and milk compared to controls (P = 0.05). A subsequent experiment was performed to determine if supplementing the sow diet with 1% PFO improved growth and reduced circulating markers of acute inflammation and stress in the offspring. Plasma was harvested from piglets (16 /treatment group) on d 0 (d of weaning) and d 1 and 3 postweaning. Pigs from the 1% PFO treatment group weighed more (P = 0.03) on d 3 postweaning and had a greater (P ˂ 0.05) n-3:n-6 PUFA ratio in plasma on each day sampled compared to 0% PFO controls. There was an overall treatment effect on plasma total cortisol (P = 0.03) and haptoglobin (P = 0.04), with lesser concentrations in pigs on the 1% PFO diet. Plasma corticosteroid-binding globulin (CBG) concentrations were not different between treatment groups but were less (P ˂ 0.001) on d 1 and 3 when compared to d 0. The resultant free cortisol index [FCI (cortisol/CBG)] was less (P = 0.02) on d 1 and 3 for pigs from the 1% treatment group compared to the controls. An exvivo lipopolysaccharide (LPS) challenge of whole blood collected on d 0 and 1 was used to determine if 1% PFO attenuated release of inflammatory cytokines (IL-1β, IL-6, and TNF-α). Blood from pigs within the 1% PFO treatment group tended (P = 0.098) to have a lesser mean concentration of TNF-α in response to LPS compared to blood from controls. These results suggest that providing a PFO supplement as 1% of the diet to sows beginning in late gestation and during lactation can increase the n-3:n-6 PUFA ratio in their offspring, which may improve growth and reduce the acute physiological stress response in the pigs postweaning.
The Swine Vet Center (SVC), a clinic with 15 veterinarians focused on pig health, launched a new website to keep its customers and the pork industry updated on its latest services, ideas and initiatives. “For us, nothing will ever replace face-to-face contact with our customers, but we wanted to expand our online presence and help the pork industry develop a better understanding of who we are and our approach to swine medicine,” said Dr. Laura Bruner, a veterinarian at SVC who was actively involved with the website’s development. In addition to new veterinarian profiles and an overview of SVC’s services, the site features a section called "SVC News," which includes articles written by or involving the clinic’s veterinarians. SVC also announced that the development of a new e-newsletter to keep the pork industry updated on the latest trends and ideas in pig health. To subscribe, click here. SVC said it has come a long way since 1990, when three veterinarians hung out a shingle in St. Peter, Minn., to service the flourishing pork industry in the Midwest. The clinic’s customers have changed, too. Today, SVC serves producers in many states, ranging from major pork production companies with 25,000 to 150,000-plus sows to traditional family farms with 500-2,400 sows.