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Background: Methane (CH4) oxidation driven by soil aerobic methanotrophs demonstrates the capacity of grassland as a CH4 sink. Methods: In this study, we compared the oxidation characteristics of atmospheric‐level and elevated concentration (10%) CH4 in a typical grassland (steppe) on the Loess Plateau, an alpine meadow (meadow) on the Qinghai‐Tibet Plateau, and an inland arid‐area artificial grassland (pasture) in northwest China and investigated the communities of active methanotrophs and their contribution to CH4 oxidation using DNA‐based stable‐isotope probing and Illumina Miseq sequencing. Results: The results showed that the oxidation of atmospheric CH4 only occurred in steppe and meadow soils where the USCγ group of methanotrophs was numerically dominant in the methanotroph community. Pasture soils, with their very low relative abundance of USCγ, did not show atmospheric CH4 oxidation. However, a DNA‐stable isotope probing experiment with 10% CH4 indicated that conventional CH4 oxidizers (Methylocaldum and Methylocystis) rather than USCγ communities assimilated significant amounts of 13CH4 for growth. Conclusions: The CH4 oxidation mechanisms in the three experimental grassland soils varied significantly. The USCγ group may be obligate oligotrophic microorganisms or their growth requires specific unknown conditions. [ABSTRACT FROM AUTHOR]

Background: In the Western Highlands of Cameroon (WHC), information on the nutritional value of fodder species consumed by ruminants is very limited. Methods: Through interviews with farmers and monitoring of animals on the range, information was obtained on the types of fodder resources consumed by the ruminants. Samples of each forage species were collected in 15 districts, mixed, chopped, and dried in a ventilated oven at 60°C, and then ground for chemical composition analysis. Results: Twenty-two forage species were identified. Among these species, Vernonia amygdalina (29.43% ± 0.45% dry matter [DM]) and Pennisetum clandestinum (87.21% ± 1.33% DM) were, respectively, the highest in protein and neutral detergent fiber contents. Manihot esculenta was one of the most energy-rich forages in terms of forage unit for lactation and forage unit for meat production. Hierarchical ascending classification revealed three main groups of forages, respectively, rich in crude fiber (Group 1), protein (Group 2), and energy (Group 3). Conclusions: The present study identified 22 forage species browsed by ruminants in WHC. Further studies should be carried out to determine the antinutritional factors and to evaluate their nutrient value using in vitro or in situ digestibility techniques. [ABSTRACT FROM AUTHOR]

Although domestic cavies are widely used in sub-Saharan Africa as a source of meat and income, there are only a few studies of their population structure and genetic relatedness. This seminal study was designed with the main objective to assess the genetic diversity and determine the population structure of cavy populations from Cameroon to guide the development of a cavy improvement program. Sixteen microsatellite markers were used to genotype 109 individuals from five cavy populations (Wouri, Moungo and Nkongsamba in the Littoral region, and Mémé and Fako in the Southwest region of Cameroon). Twelve markers worked in the five populations with a total of 17 alleles identified, with a range of 2.9 to 4.0 alleles per locus. Observed heterozygosity (from 0.022 to 0.277) among populations was lower than expected heterozygosity (from 0.42 to 0.54). Inbreeding rates between individuals of the populations and between individuals in each population were 59.3% and 57.2%, respectively, against a moderate differentiation rate of 4.9%. All the tested loci deviated from Hardy-Weinberg equilibrium, except for locus 3. Genetic distances between populations were small (from 0.008 to 0.277), with a high rate of variability among individuals within each population (54.4%). Three distinct genetic groups were structured. This study has shown that microsatellites are useful for the genetic characterization of cavy populations in Cameroon and that the populations investigated have sufficient genetic diversity that can be used to be deployed as a basis for weight, prolificacy and disease resistance improvement. The genetic of diversity in Southern Cameroon is wide and constitute an opportunity for cavy breeding program., (© 2017 Journal Of Animal Production.)