Development of methane emission factors for enteric fermentation in cattle from Benin using IPCC Tier 2 methodology.

The objective of this study was to develop emission factors (EF) for methane (CH4) emissions from enteric fermentation in cattle native to Benin. Information on livestock characteristics and diet practices specific to the Benin cattle population were gathered from a variety of sources and used to estimate EF according to Tier 2 methodology of the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories. Most cattle from Benin are Bos taurus represented by Borgou, Somba and Lagune breeds. They are mainly multi-purpose, being used for production of meat, milk, hides and draft power and grazed in open pastures and crop lands comprising tropical forages and crops. Estimated enteric CH4 EFs varied among cattle breeds and subcategory owing to differences in proportions of gross energy intake expended to meet maintenance, production and activity. EFs ranged from 15.0 to 43.6, 16.9 to 46.3 and 24.7 to 64.9 kg CH4/head per year for subcategories of Lagune, Somba and Borgou cattle, respectively. Average EFs for cattle breeds were 24.8, 29.5 and 40.2 kg CH4/head per year for Lagune, Somba and Borgou cattle, respectively. The national EF for cattle from Benin was 39.5 kg CH4/head per year. This estimated EF was 27.4% higher than the default EF suggested by IPCC for African cattle with the exception of dairy cattle. The outcome of the study underscores the importance of obtaining country-specific EF to estimate global enteric CH4 emissions.

Toxicity and gastric tolerance of essential oils from Cymbopogon citratus, Ocimum gratissimum and Ocimum basilicum in Wistar rats.

Oils of Cymbopogon citratus, Ocimum gratissimum and Ocimum basilicum are widely used for their medicinal properties, and as food flavours and perfumes. Recently in a study in West Africa, these oils have been recommended to combat Fusarium verticillioides and subsequent fumonisin contamination in stored maize, but their toxicological profile was not investigated. The current study was undertaken to provide data on acute and subacute toxicity as well as on gastric tolerance of these oils in rat. For this purpose, the oils were given by gavage to Wistar rats for 14 consecutive days. The animals were observed daily for their general behaviour and survival, and their visceral organs such as stomach and liver were taken after sacrifice for histological analyses. A dose-dependent effect of the tested oils was observed during the study. Applied at doses generally higher than 1500 mg/kg body weight, the oils caused significant functional damages to stomach and liver of rat. Unlike the other oils, administration of O. gratissimum oil did not result in adverse effects in rat liver at the tested doses. The no observed adverse effect level (NOAEL) of the tested oils has been established. The three tested oils can be considered as safe to human when applied on stored maize at recommended concentrations.

Comparative chemical and analgesic properties of essential oils of Cymbopogon nardus (L) Rendle of Benin and Congo.

The chemical and analgesic comparison of essential oils of Cymbopogon nardus (L) Rendle of Benin and Congo was investigated. The chemical analysis wa carried out by using GS/MS for identification of components of the two essential oils while acetic acid-induced writhings, hot plate and tail flick test models were used for analgesic activity. The results showed that the two essential oils exhibited comparable activity on acetic acid-induced writhings, however, the essential oil of Benin induced more significant effect on hot plate model while the Congolese specie showed more effect in the tail flick test. These observations could be explained by some qualitative and/or quantitative differences observed between the constituents of the two essential oils studied.