Over the last decade, food waste has been one of the major issues globally as it brings a negative impact on the environment and health. Rotting discharges methane, causing greenhouse effect and adverse health effects due to pathogenic microorganisms or toxic leachates that reach agricultural land and water system. As a solution, composting is implemented to manage and reduce food waste in line with global sustainable development goals (SDGs). This review compiles input on the types of organic composting, its characteristics, physico-chemical properties involved, role of microbes and tools available in determining the microbial community structure. Composting types: vermi-composting, windrow composting, aerated static pile composting and in-vessel composting are discussed. The diversity of microorganisms in each of the three stages in composting is highlighted and the techniques used to determine the microbial community structure during composting such as biochemical identification, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), terminal restriction fragment length polymorphism (T-RFLP) and single strand-conformation polymorphism (SSCP), microarray analysis and next-generation sequencing (NGS) are discussed. Overall, a good compost, not only reduces waste issues, but also contributes substantially to the economic and social sectors of a nation.

Ram sperm cryopreservation is crucial for artificial insemination and genetic improvement programs in the small ruminant industry. Semen handling and cryopreservation can negatively affect sperm quality irrespective of the storage conditions and extenders used. Studies have reported an increase in reactive oxygen species in ram sperm during cryopreservation, leading to oxidative stress. Oxidative stress significantly compromises the sperm fertilising ability by inducing oxidative damage to protein, lipid, and nucleic acid components of the sperm cell. The supplementation of antioxidants to semen extenders before cryopreservation can minimise this detrimental effect. Natural antioxidants have emerged as an economical and effective source of additives to preserve and enhance ram sperm quality during semen preservation. This review presents an overview on harmful effects of oxidative stress on ram spermatozoa, extrinsic and intrinsic factors responsible for occurrence of oxidative stress, as well as natural antioxidants and their potential as an additive for sperm quality enhancers in different ram breeds. Taken together, we suggest that synergistic combinations of antioxidants that are economically feasible, such as resveratrol with vitamins C or E, could be the way forward, but warrant further investigations into dosage versus toxicity, standardised extraction protocols, and breed-specificity in their supplementation in semen extenders.