Seasonal Differences in Fecal Microbial Community Structure and Metabolism of House-Feeding Chinese Merino Fine-Wool Sheep

The digestive tract microorganisms play a very important role in the host's nutrient intake, environmental suitability, and affect the host's physiological mechanism. Previous studies showed that in different seasons, mammalian gut microbes would be different. However, most of them are concentrated in wild animals. It remains unclear how seasonal change affects the gut microbes of Chinese merino fine-wool Sheep. Therefore, in this experiment, we continuously collected blood and feces samples of 50 Chinese merino fine-wool sheep in different seasons, measured the physiological indicators of blood, and passed 16S rRNA amplicon sequencing, determined the microbial community structure of fecal microorganisms and predicted flora function by PICRUSt. The results of blood physiological indicators showed that WBC, Neu and Bas in spring were significantly higher than those of other seasons. Fecal microbial sequencing revealed seasonal changes in gut microbial diversity and richness. Among them, Chinese merino fine-wool sheep had the highest gut microbes in summer. Firmicutes and Bacteroidetes were the dominant phyla, and they were unaffected by seasonal fluctuations. LEfSE analysis was used to analyze representative microorganisms in different seasons. The Lachnospiraceae and its genera (Lachnospiraceae_NK4A136_group, Lachnospiraceae_AC2044_group, g_unclassified_f_ Lachnospiraceae) were representative microorganisms in the three seasons of spring, summer and winter with harsh environmental conditions; while in autumn with better environmental conditions, the Ruminococcaceae and its genus (Ruminococcaceae_UCG-009 and Ruminococcaceae_UCG-005) were the representative microorganism. In autumn, the ABC transporter and the pyruvate metabolic pathway were significantly higher than other seasons. Correlation analysis results showed that Lachnospiraceae participated in the ABC transporters metabolic pathway, which caused changes in the blood physiological indicators. Overall, our results showed that, in response to seasonal changes, Chinese merino fine-wool sheep under house-feeding have adjusted their own gut microbial community structure, causing changes in the metabolism, and thus changing the physiological conditions of the blood. In the cold season, producers should focus on regulating the nutritional level of feed, enhancing the level of butyric acid in young animals to increase the ABC transporter, resist the external harsh environment, and improve the survival rate.

Dietary High Chromium-Methionine Supplementation in Summer-Exposed Finishing Lambs: Impacts on Feed Intake, Growth Performance, and Blood Cells, Antioxidants, and Minerals

This study aimed to investigate the effect of dietary high doses of chromium-methionine (CrMet) supplementation on blood hemato-biochemical parameters and growth performance of finishing lambs reared under warm condition with average temperature-humidity index (THI) of 85.8 unit. Fifteen male lambs (31.9 ± 1.2 kg) fed with either un-supplemented diet (CON) or supplemented with 1.5 (Cr1.5) and 3 (Cr3) mg of Cr/kg dry matter (DM) for 8 weeks. The results showed that high levels of supplemental Cr had no negative impacts on red (RBC) and white blood cells (WBC). Blood total antioxidant capacity (TAOC) tended to be higher in CrMet-fed lambs than those of CON (P < 0.1). Serum malondialdehyde (MDA), as a lipid peroxidation marker, was, respectively, 20.24 and 22.1%, lower in lambs given 1.5 and 3 mg of chromium comparing those of CON (P < 0.05). Moreover, erythrocyte glutathione peroxidase (GSH-PX, U/dL) displayed higher activity in Cr3 (421.2) group than those of CON (334.6) and Cr1.5 (351.2) groups (P < 0.05). Accordingly, GSH-PX activity per gram hemoglobin (U/gHb) was 45.9% greater in lambs of Cr3 than the CON (P < 0.05). Furthermore, feeding 3 mg of Cr led to increased erythrocyte superoxide dismutase (SOD) activity (P < 0.05): as such, SOD was 1193.1, 1281.5, and 1433.0 U/gHb in CON, Cr1.5, and Cr3, respectively. Chromium supplementation linearly decreased serum iron concentration (P < 0.05), but neither blood calcium, phosphorous, copper, zinc, and glucose concentrations nor aspartate aminotransferase and alanine aminotransferase activities were affected by supplemental CrMet. In comparison with CON (1250), lambs in Cr1.5 (1199) and Cr3 (1192) groups had lower daily feed intake (g/d, P < 0.01). In addition, feed to gain ratio was 21.5% lower in the Cr3 group than the control (P < 0.05). Collectively, these findings suggest that feeding summer-exposed finishing lambs with 3 mg of Cr/kg DM improves blood antioxidant status and feed to gain efficiency without adverse effects on lambs' health and metabolism.

Pest flies on dairy farms affect behaviour and welfare of dairy cows during summer season

Monitoring of changes in the behaviour of dairy cows related to the occurrence of insects in the stable and in the milking parlour was carried out on a selected dairy farm during the summer season. The effect of the number of insects on the occurrence of huddling of dairy cows in the stable was proved. Huddling occurred significantly (P = 0.003) more often when the number of insects captured by fly glue traps exceeded 500 individuals. The occurrence of pest flies affected also the behaviour of dairy cows during milking. With the increasing number of insects captured by glue traps in the milking parlour, the cows more frequently kicked off the milking units (r = 0.944, P < 0.001) and defecated (r = 0.940, P < 0.001) during milking. In addition, the increasing number of captured insects correlated with a significantly lower milk yield in cows (r = -0.709, P < 0.001). The number of insects in the stable also correlated with the incidence of mastitis in dairy cows on the monitored farm (r = 0.681, P < 0.001) during the summer season. The study shows that pest flies affect the behaviour of cows which is further reflected in their health, milk production and thus the overall farm performance.