Selenium (Se), a micro element was well known for its toxicity at earlier times. But, presently it is listed to be an essential mineral which is required for sound health, better immunity, and efficient reproductive functions of livestock. There is variation in the status of Se in animals and plants across the world based on different geological conditions. Se concentrations of plants are closely related with those of its soil concentration. The deficiency of Se is associated with many health problems viz increased neonatal mortality, lowered immunity poor suckling reflex and white muscle disease in animals. There is significant role of Se in the reproduction of animals. The selenoproteins such as, Glutathione peroxidase 4 (GSH-Px4) and SELENOP have a regulatory role in male reproduction. GSH-Px4 has distinct antioxidant and structural properties and is expressed in testes. The peroxidation of Leydig cells is protected by SELENOP. The specific role of Se involves development of seminiferous tubules, growth of testicular tissues, in process of spermatogenesis, steroidogenesis and in synthesis and secretion of reproductive hormones like follicular stimulating hormone (FSH) and luteinizing hormone (LH). In female reproduction, the supplementation of Se may reduce the incidence of metritis and ovarian cysts and decreases the embryonic mortality. Currently, due attention is given on dietary Se supplementation through different (inorganic, organic and nano) forms of Se.

To evaluate the methane generation potential and digestibility of different (normal and three high-quality protein maize [HQPM]) varieties of maize fodder with goat rumen liquor in vitro. Methane production potential and digestibility of different varieties of maize fodder were tested in in vitro gas production test. Seven varieties of maize, four normal (HTHM 5101, DHM 117, HM 5, and Shaktiman/900 M Gold), and three high-quality protein (HQPM 5, HQPM 7, and HQPM 9/Vivek) were grown in different plots under the same environmental and agro-climatic conditions. Fodders were harvested at 45-50 days of sowing, and the representative samples of fodder from different varieties of maize were collected for analysis. Dried and grinded form of these maize fodder varieties was tested for gas, methane, and digestibility using goat rumen microflora in in vitro gas syringes. Gas production (ml/g dry matter [DM]) was highest for HM5 variety (97.66, whereas lowest for HQPM 9 variety (64.22). Gas production (ml/g degraded DM [DDM]) and methane (%) were statistically similar in different varieties of maize fodder. The methane production expressed as ml/g DM and ml/g DDM was significantly (p<0.05) highest for HM 5 (14.22 and 26.62) and lowest for DHM 117 variety (7.47 and 14.13). The in vitro DM digestibility (%) and in vitro organic matter digestibility (%) varied from 47.48 (HQPM 5) to 52.05 (HQPM 9) and 50.03 (HQPM 7) to 54.22 (HM 5), respectively. The present study concluded that DHM 117 maize variety fodder has lowest methane generation potential and incorporating it in the dietary regime of ruminants may contribute to lower methane production.

A study was conducted on growing sheep to investigate the effect of two selected levels of biowaste of Padina gymnospora on feed intake, digestibility, daily enteric methane (CH₄) emission, growth performance, and rumen metagenome. We randomly divided the 18 growing male sheep into three groups of six animals each. The animals were fed on a basal diet comprising finger millet straw (Eleusine coracana) and a concentrate mixture in a 35:65 ratio. The sheep in the control group (C) were offered a concentrate mixture without waste, whereas the wheat bran in the concentrate mixture in test group I (A₂) and test group II (A₅) was replaced (w/w) with the biowaste of Padina gymnospora at a level of 3.07 and 7.69%, respectively. The biowaste of Padina gymnospora at the above levels in concentrate constituted 2 and 5% of the diet. A significant decrease of 28.4% in daily enteric CH₄ emission (g/d) was reported in the A₅ group, whereas the difference in daily enteric CH₄ emission between the C and A₂ & A₂ and A₅ groups did not prove significant. The inclusion of Padina gymnospora biowaste did not affect the nutrient intake and digestibility among the groups. The inclusion of Padina gymnospora biowaste in the A₅ group resulted in a significant reduction (p = 0.0012) in daily CH₄ emissions compared with group C; however, no significant differences were observed in daily CH₄ emissions between groups C–A₂ (p = 0.0793) and A₂–A₅ (p = 0.3269). Likewise, the adjustment of data to CH₄ emissions per 100 g of organic matter intake indicated a substantial decrease in the A₅ group relative to C. The energy loss in CH₄ as a percentage of GE relative to group C decreased significantly (−23.4%) in the A₅ group; however, this reduction was not associated with an increase in productivity, as almost similar average daily gain (p = 0.827) was observed in the groups. The replacement of wheat bran with the biowaste of Padina gymnospora significantly decreased the numbers of total protozoa and holotrichs in the A₅ group. Irrespective of the group, the Bacteroidota was the single largest phylum in the rumen metagenome, representing >60% of the microbiota. However, the abundance of Bacteroidota was similar among the groups. The methanogenic phyla Euryarchaeota was the 5th most abundant; however, it constituted only 3.14% of the metagenome. The abundance of Desulfovibrio was significantly higher in the A₅ group as compared with the control. In conclusion, the significant increase in the abundance of sulfate-reducing bacteria and reduction in protozoal numbers led to a significant reduction in CH₄ emissions with the incorporation of biowaste of Padina gymnospora at a 5% level of the diet.