Trace minerals for improved performance: a review of Zn and Cu supplementation effects on male reproduction in goats.

Minerals are required in small amounts but play significant roles in many physiological functions related with growth, reproduction, and health of goats such as biochemical, molecular systems, and optimized enzymatic activities due to their roles as co-factors to metalloenzymes. Among them, zinc (Zn) and copper (Cu) are leading essential elements in goat nutrition, because of their role across several biological functions. The proportion of these minerals availability and absorption from the ingested feed is usually less, because of their complexities with un-degradable parts of feed resources. Hence, their exogenous supplementation is required for normal animal functions. On this background, this review presents findings associated with supplementation of these minerals in organic form as a way for improving the fertility of male goats with special focus on physico-chemical-kinetics of the semen for improving the application of reproductive technologies. This review emphasizes the organic sources of these minerals to replace the inorganic sources, based on their significance in improving semen qualities, antioxidant protection, and mediation of molecular activities. This review also discusses salient routes of Zn and Cu absorption and identifies the need for molecular exploration for positive outcomes with supplementation of these minerals as an area of the future goat nutrition-reproduction improvement strategy.

DNA double-strand break repair in Penaeus monodon is predominantly dependent on homologous recombination.

DNA double-strand breaks (DSBs) are mostly repaired by nonhomologous end joining (NHEJ) and homologous recombination (HR) in higher eukaryotes. In contrast, HR-mediated DSB repair is the major double-strand break repair pathway in lower order organisms such as bacteria and yeast. Penaeus monodon, commonly known as black tiger shrimp, is one of the economically important crustaceans facing large-scale mortality due to exposure to infectious diseases. The animals can also get exposed to chemical mutagens under the culture conditions as well as in wild. Although DSB repair mechanisms have been described in mammals and some invertebrates, its mechanism is unknown in the shrimp species. In the present study, we show that HR-mediated DSB repair is the predominant mode of repair in P. monodon. Robust repair was observed at a temperature of 30 °C, when 2 µg of cell-free extract derived from hepatopancreas was used for the study. Although HR occurred through both reciprocal recombination and gene conversion, the latter was predominant when the bacterial colonies containing recombinants were evaluated. Unlike mammals, NHEJ-mediated DSB repair was undetectable in P. monodon. However, we could detect evidence for an alternative mode of NHEJ that uses microhomology, termed as microhomology-mediated end joining (MMEJ). Interestingly, unlike HR, MMEJ was predominant at lower temperatures. Therefore, the results suggest that, while HR is major DSB repair pathway in shrimp, MMEJ also plays a role in ensuring the continuity and stability of the genome.