Effect of capsaicin supplementation on lactational and reproductive performance of Holstein cows during summer

Context Summer ambient temperature and humidity are major factors negatively influencing the physiology and the productive and reproductive efficiency of dairy cows. Various management and breeding approaches may be useful for maintaining productivity in dairy cows during summer to minimise these effects. Aims The experiment was designed to test a natural phytochemical supplementation of capsaicin (CPS), followed by a specific oestrus synchronisation protocol as a means to maintain productivity and reproductive performance of Chinese Holstein cows during summer in Hubei province, China. Methods Lactating Chinese Holstein cows (n = 109) were randomly divided into four groups and supplemented with 0 (control, n = 27), 20 (CPS-20, n = 26), 40 (CPS-40, n = 28) and 60 (CPS-60, n = 28) mg of capsaicin (CPS) per kg of total mixed ration respectively for continuous 30 days initiated on 10 July 2018. Milk production and composition were measured over 45 days from the start of CPS supplementation. After CPS supplementation, all cows were synchronised through a modified Ovsynch oestrus synchronisation protocol, and reproductive variables were recorded. Metabolic parameters were measured on the days before CPS supplementation, artificial insemination (AI) and 50 days post-AI. Key results Highest (P < 0.05) milk production were found in the CPS-40 group, and highest total solids and milk fat in the CPS-20 and CPS-40 groups. Milk urea nitrogen and milk fat were generally increased in CPS supplemented cows compared with the control group. Significant increases (P < 0.05) in oestrus response, ovulatory follicle size, ovulation rate and pregnancy rates were observed in the CPS-40 group compared with other groups. Glucose, lipoprotein esterase and aspartate aminotransferase were increased (P < 0.05) in CPS-40 and CPS-60 supplemented groups at the time of AI and 50 days post-AI. Conclusions CPS supplementation has the capacity to maintain milk yield, milk composition and serum metabolites in Chinese Holstein dairy cows during summer. The synergistic effect of CPS and the modified oestrus synchronisation protocol also improved reproductive variables of the cows. Implications Adoption of CPS as a supplement along with oestrus synchronisation could be a useful and economical strategy for dairy herd keepers to improve herd performance during summer.

Genetic variation of the adenylyl cyclase 3 (AC3) locus and its influence on type 2 diabetes and obesity susceptibility in Swedish men

OBJECTIVE

Our previous study using the Goto-Kakizaki rat implicates that the adenylyl cyclase 3 (AC3) is a candidate gene for genetic study of metabolic disorders. The present study aimed to investigate the susceptibility of genetic variation of the AC3 gene in type 2 diabetes (T2D) patients and obese subjects.

SUBJECTS AND METHODS

Variation screening in the putative promoter and validation of single nucleotide polymorphisms (SNPs) covering the AC3 gene were performed. In total, 630 Swedish men, including 243 T2D patients (BMI from 18.4 to 45.6 kg m(-2)), 199 obese subjects with normal glucose tolerance (NGT, BMI> or =30 kg m(-2)) and 188 control subjects (NGT, BMI< or =26 kg m(-2)), were genotyped.

RESULTS

A novel variant -17A/T in the promoter was identified, but no significant association of this polymorphism with T2D was found. SNPs rs2033655 C/T and rs1968482 A/G were found to be significantly associated with obesity when T2D patients had BMI> or =30 kg m(-2) (P=0.003 and 0.005). The significance was borderline in T2D patients with BMI<30 kg m(-2) (P=0.051 and 0.084) and disappeared in T2D patients with BMI< or =26 kg m(-2). Importantly, analysis in obese subjects with NGT demonstrated that these two polymorphisms were strongly associated with obesity per se (P=0.028 and 0.003). Furthermore, analyses for diplotypes (haplotypic genotypes) predicted an association with BMI in obese subjects.

CONCLUSIONS

The present study provides the first evidence that AC3 polymorphisms confer the risk susceptibility to obesity in Swedish men with and without type 2 diabetes.