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.

Dietary boron supplementation enhances sperm quality and immunity through influencing the associated biochemical parameters and modulating the genes expression at testicular tissue

INTRODUCTION

Dietary boron improves immune and antioxidant status and calcium metabolism in mammals. However, till date the effects of dietary boron supplementation on male reproduction, especially on sperm production and sperm quality in farm animals are not documented.

OBJECTIVE

The present study was aimed to investigate the influence of dietary boron on semen production, semen quality, immunity and molecular changes in the testis, blood and seminal plasma and to assess the interrelationship with other minerals in male goats.

METHODOLOGY

The study was conducted in 21 adult male goats divided into 3 groups (control, boron and selenium supplemented groups, n = 7 each). In boron group, boron was supplemented at 40 ppm and in selenium group, selenium was supplemented at 1 ppm over and above the basal level. In control group, only the basal diet was fed without supplementary boron or selenium. The feeding trial was carried out for 60 days. Selenium was taken as a positive control for the dietary boron supplementation experiment. Following feeding trials, the sperm concentration, kinematics and functional attributes, immunity and molecular level changes in the testis, biomolecular changes in the blood and seminal plasma and also interrelationship with other minerals were studied.

RESULTS

The average sperm concentration (million/ml) and the total sperm production (million/ejaculate) were significantly (p < 0.05) increased in boron supplemented group when compared to selenium and control groups. The boron levels in blood plasma (r = 0.65) and seminal plasma (r = 0.54) showed a positive correlation with sperm progressive motility. Blood and seminal plasma metabolic biomarker namely, aspartate aminotransferase (AST) (p < 0.01) was significantly lower in the boron and selenium supplemented group than control, while alanine aminotransferase (ALT) (p < 0.05) was significantly lower in the boron supplemented group than selenium and control group. There was a significant increase in the mRNA expression of serine proteinase inhibitor (SERPIN) and interferon γ (IFNγ) in the testis of boron supplemented than the control group. Boron supplementation up-regulated the immune-regulatory gene, interleukin 2 (IL2) and antioxidant gene, catalase (CAT) in the peripheral blood mononuclear cells (PBMC). On contrary, toll-like receptor 2 (TLR2) mRNA expression was significantly (p < 0.05) down-regulated in boron and selenium supplemented groups.

CONCLUSION

The study revealed that dietary boron supplementation increased the sperm output, sperm motility and enhanced the immune and antioxidant defense capacity in male goats. The improved semen quality can be attributed to enhanced expression of testicular SERPIN, a crucial protein for the regulation of spermatogenesis process.

Relationship between seminal plasma tuberoinfundibular peptide of 39 residues and sperm functional attributes in buffalo (Bubalus bubalis)

The buffalo seminal plasma protein profile and its relationship with sperm quality have not been studied in detail. Thus, the aim of the present study was to profile buffalo seminal plasma proteins and to assess the relationship between differentially expressed proteins and sperm characteristics. Semen samples (n = 44) were collected from 11 Murrah buffalo bulls (four ejaculates from each animal) and seminal plasma protein profiling was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Matrix-assisted laser desorption ionisation time-of-flight analysis of one of the differentially expressed proteins, namely the 11-12 kDa protein, identified it as tuberoinfundibular peptide of 39 residues (TIP39). Western blot analysis confirmed the presence of TIP39, with TIP39 expression in seminal plasma varying among bulls. Based on TIP39 levels, bulls were classified into two groups, those with high and low protein. The percentages of spermatozoa positive for mitochondrial membrane potential test, chromatin distribution test, synthetic media sperm penetrability test and acrosomal integrity test were significantly (P < 0.05) high in the high protein group. The present study is the first to demonstrate the presence of TIP39 in buffalo seminal plasma and the positive effect of TIP39 on the functional parameters and fertilising ability of spermatozoa.