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Probiotics are the most promising alternative to antibiotics for improving animal production and controlling pathogenic infections, while strains derived from natural hosts are considered highly desirable due to their good adaptation to the gastrointestinal tract. The aim of this study was to screen Lactobacillus with broad-spectrum antibacterial activity from broilers fed an antibiotic-free diet and evaluate their potential as poultry probiotics. A total of 44 lactic acid bacteria (LAB) strains were isolated from the intestines of healthy broilers, among which 3 strains exhibited outstanding antimicrobial activity and were subsequently identified through 16S rRNA sequencing as Enterococcus faecium L8, Lactiplantibacillus plantarum L10, and Limosilactobacillus reuteri H11. These three isolates demonstrated potent bacteriostatic activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella cholerae, with inhibition zones ranging from 15.67 ± 1.53 to 21.33 ± 0.58 mm. The selected LAB strains exhibited high tolerance to acid and bile salts, with L. reuteri H11 displaying the highest survival rate (ranging from 34.68% to 110.28%) after exposure to 0.3% (w/v) bile salts for 6 h or a low pH environment (pH 2, 2.5, and 3) for 3 h. Notably, L. reuteri H11 outperformed other strains in terms of hydrophobicity (84.31%), auto-aggregation (53.12%), and co−aggregation with E. coli ATCC 25922 (36.81%) and S. aureus ATCC 6538 (40.20%). In addition, the three LAB isolates were either fully or moderately susceptible to the tested antibiotics, except for strain L8, which resisted gentamycin and vancomycin. Consequently, these three LAB strains, especially L. reuteri H11, isolated from the intestines of broiler chickens, represent promising probiotic candidates that can be employed as feed additives to enhance production performance and control poultry pathogens. [ABSTRACT FROM AUTHOR]

This paper was aimed at the question of whether the feeding of pasteurized abnormal milk affects the growth performance and serum indexes of calves, a total of 240 healthy newborn Holstein calves were selected as experimental animals. The calves were divided into two treatment groups by random block design of pasteurized abnormal milk (PAM) group and milk replacer powder (MR) group. With the same starter, the trial period was 12 weeks. The results show that the milk intake and feed intake of PAM group are significantly lower than those of MR group (P <0. 05). At 5 weeks of age, the body weight of calves in PAM group is significantly higher than that in MR group (P <0. 01). At 0 to 5 weeks, the average daily gain(ADG) of PAM group is significantly higher than that of MR group (P < 0. 01). The body length and abdominal circumference of PAM group is significantly lower than those of MR group (P <0. 05). The fecal score of calves in PAM group is significantly lower than that in MR group (P <0. 01). At 0 to 12 weeks of age, there is no significant difference in average serum glucose and total protein, while albumin and globulin in PAM group are significantly higher than those in MR group (P <0. 05). At 0 to12 weeks of age, the average serum cortisol mass concentration in PAM group is significantly higher than that in MR group (P <0. 05), and there is no significant difference in INS, IL-6 and IL-1β (P > 0. 05) . The feed intake, body length and abdominal circumference of calves are reduced by feeding pasteurized abnormal milk, but daily weight gain is not affected. And serum albumin and globulin are increased, but calf stress is increased. [ABSTRACT FROM AUTHOR]

Heat stress (HS) has a negative impact on the health and performance of dairy cows, resulting in economic losses. Damage to the intestinal epithelium is the main cause of the adverse effects of heat stress on bovine health. This study investigated the repair capability of L-arginine (L-Arg) in reducing the adverse effects of HS on bovine intestinal epithelial cells (BIECs). BIECs were treated as follows: (1) control cells were cultured at 37 °C continuously and received no L-Arg; (2) cells in HS group were grown at 42 °C for 6 h followed by 12 h at 37 °C; and (3) the L-Arg group was cultured at 42 °C for 6 h, then treated with L-Arg at 37 °C for 12 h. HS disrupted redox homeostasis and reduced viability in BIECs, while treatment with L-Arg (6 mmol/L) for 12 h markedly reduced the negative effects of HS. L-Arg protected cells by preventing HS-induced changes in mitochondrial membrane-potential, inflammation, apoptosis-related gene expression and regulation of antioxidant enzymes. The above results indicated that L-Arg reduced the level of damage from HS in BIECs by lowering oxidant stress and inflammation, suggesting that L-Arg could be an effective dietary addition to protect cows from adverse intestinal effects caused by HS. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of dietary supplementation with Glycyrrhiza polysaccharide (GCP) on growth performance, serum biochemistry, immunity, and egg laying in female quail. 300 1-day-old female quail were sorted into four dietary treatments with five replicate cages of 15 birds each. The basic diet in the four treatment groups was supplemented with 0, 500, 1000 and 1500 mg/kg GCP, and the experiment continued for 80 days. Results showed that dietary supplementation with GCP significantly (p < 0.05) increased average daily gain in a dose-dependent fashion, and decreased (p < 0.05) the feed-to-gain ratio and mortality. The relative weights of the thymus and bursa of Fabricius increased (p < 0.05) linearly with increasing dose of GCP from 0 to 1500 mg/kg on day 20. GCP birds showed higher serum levels of protein, glucose, immunoglobulin A and immunoglobulin M, but lower serum triglycerides (p < 0.05) on day 50. GCP increased (p < 0.05) average laying rate and average egg weight linearly from days 60 to 80, whereas feed to egg ratio was decreased (p < 0.05). Taken together, these results revealed that GCP could improve growth performance, serum biochemistry, immunity, and egg laying in female quail. Therefore, GCP may be a potential replacement for antibiotic growth promoters in poultry. [ABSTRACT FROM AUTHOR]