2. Universidad Cardenal Herrera-CEU

Changes in semen microbiota are associated with alterations to sperm quality and fertility. However, the microbiota from most livestock species has not yet been studied. Goats are seasonal breeders, but semen microbiota has never been described in this species, and it is unknown how seasonality affects it. Our study objective is 2-fold: to describe the microbiota in goat buck ejaculates and to determine if it differs between breeding and non-breeding seasons. Semen from six males of the Murciano-Granadina breed was collected during both seasons. Two replicates were performed per male and season on different days. The microbiota was characterized by genomic sequencing technology. Sperm quality was also evaluated. Repetition was not significant for the studied variables. Sperm velocities were higher for the breeding than for the non-breeding season. The ejaculates from both seasons also differed in the proportion of apoptotic spermatozoa. The five dominant phyla were Firmicutes, Proteobacteria, Fusobacteria, Actinobacteria, and Bacteroidetes during the breeding season and Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Cyanobacteria during the non-breeding season. The dominant genus during both seasons was Ureaplasma. Differences in microbial community structure (the beta diversity) were found. A decrease in the relative abundance of the genus Faecalibacterium and an increase in the genera Sphingomonas and Halomonas were observed in the ejaculates collected during the breeding season. Sphingomonas and Faecalibacterium abundance favorably and unfavorably correlated with sperm quality, respectively. In conclusion, the semen microbiota from goat bucks varies between breeding and nonbreeding seasons, and the microbiota remains stable for 7 days within a season. In addition, the genera Sphingomonas and Faecalibacterium could be possible biomarkers of semen quality in goat bucks. These results contribute to an in-depth understanding of the effects of reproductive seasonality on goat buck ejaculates.

The last third of gestation is a period of high energy and protein demand for the dam to support fetal growth and the following onset of lactation. Methionine is an essential amino acid that contributes to protein formation, fetal development, and milk synthesis; thus, is likely to have positive effects on the weight and size of the newborn and, afterward, milk yield and milk composition, which may improve growth patterns of the progeny. To test these hypotheses, we used 60 pregnant multiparous Alpine goats with similar live weights and gestational ages (~Day 100 of pregnancy; Mean SD; 1410 14 days old and 50.4 6.6 kg) and were separated into two groups: control and supplemented with the delivery. Treatments were T-MET (n = 30; received 1% herbal methionine Optimethione® dry matter based on from Day 100 of the pregnancy to delivery) or T-CTL (n = 30; served as the control and did not receive methionine). The methionine powder provided individual supplementation and was adjusted every week as the live weight and dry matter intake changed. At birth, the weight, body mass index (BMI), birth type, and sex of the kids were determined. Subsequently, the progeny was weighed weekly up to weaning. Two weeks after parturition, the milk composition was recorded weekly, and the milk yield was recorded monthly. The maternal live weight at the start (Mean SEM; T-CTL: 50.5 1.1 vs. T-MET: 50.3 1.3 kg) and end (T-CTL: 54.2 1.3 vs. T-MET: 52.8 1.4 kg) of the experiment did not differ statistically among treatments (p > 0.05); however, daily live weight changes tended to differ between groups (T-CTL: 73 10 vs. T-MET: 51 7 g day􀀀1; p = 0.06). The birth weight (T-CTL: 3.1 0.1 vs. TMET: 3.5 0.1 kg; p < 0.001), daily live weight change (T-CTL: 121 6 vs. T-MET: 141 6 g day􀀀1; p < 0.01), and weaning weight (T-CTL: 8.3 0.2 vs. T-MET: 9.3 0.3 kg; p < 0.01) differed between treatments. The BMI at birth (T-CTL: 0.28 0.01 vs. T-MET: 0.3 0.01 units kg m􀀀2; p < 0.01) and at weaning (T-CTL: 0.85 0.1 kg vs. T-MET: 1.00 0.06 units kg m􀀀2; p < 0.05) differed between treatments. Milk components (protein, fat, lactose, and solids non-fat) and milk yield were similar between treatments (p > 0.05). It is concluded that the inclusion of methionine in the maternal goat diet during the last third of gestation increases the birth and growth variables of the progeny but without significant influence on the milk yield and composition.