The present study aimed to investigate whether arginine (Arg) promotes porcine type I muscle fibres formation via improving mitochondrial biogenesis. In the in vivo study, a total of sixty Duroc × Landrace × Yorkshire weaning piglets with an average body weight of 6·55 (sd 0·36) kg were randomly divided into four treatments and fed with a basal diet or a basal diet supplemented with 0·5, 1·0 and 1·5 % l-Arg, respectively, in a 4-week trial. Results showed that dietary supplementation of 1·0 % Arg significantly enhanced the activity of succinate dehydrogenase, up-regulated the protein expression of myosin heavy chain I (MyHC I) and increased the mRNA levels of MyHC I, troponin I1, C1 and T1 (Tnni1, Tnnc1 and Tnnt1) in longissimus dorsi muscle compared with the control group. In addition, ATPase staining analysis indicated that 1·0 % Arg supplementation significantly increased the number of type I muscle fibres and significantly decreased the number of type II muscle fibres. Furthermore, 1·0 % Arg supplementation significantly up-regulated PPAR-γ coactivator-1α (PGC-1α), sirtuin 1 and cytochrome c (Cytc) protein expressions, increased PGC-1α, nuclear respiratory factor 1 (NRF1), mitochondria transcription factor B1 (TFB1M), Cytc and ATP synthase subunit C1 (ATP5G) mRNA levels and increased mitochondrial DNA content. In the in vitro study, mitochondrial complex I inhibitor rotenone (Rot) was used. We found that Rot annulled Arg-induced type I muscle fibres formation. Together, our results provide for the first time the evidence that Arg promotes porcine type I muscle fibres formation through improvement of mitochondrial biogenesis.

A number of analytical tools were applied to estimate fish species richness in a small tropical stream (Brazil) that had been sampled by conventional methods (double stick net, electrofishing) and rotenone. Three sites were compared in two seasons each and a total of 34 species were captured. The sampling efficiency of electrofishing was much better than that of the double stick net and little worse than of rotenone. No estimator was thoroughly consistent and accurate in predicting species richness on the basis of electrofishing, but the Homogenous Model, which assumes that all species have the same detection probabilities, was best. The rarefaction technique should be used with caution as it may produce misleading results in species richness predictions.

The use of synthetic acaricides in tick control is increasingly becoming more expensive. As a result, a lot of Africa's resource-poor farmers are failing to dip their cattle regularly. Natural products offer these farmers a cheaper alternative to synthetic acaricides. There is indeed a great potential for the use of Africa's huge natural resources, the plants to develop sources of acaricides to reduce the cost of tick control being locally available and potentially being able to be produced and used by farmers themselves or by cottage industries. It is, however, necessary that research centres such as ICIPE encourage the development of systematic research on natural products in order to bring about the Tephrosia vogelii leaf extracts observed to be highly toxic to one-, two- and three-host ticks and cattle sprayed with the extract had a residual protection period of 10 days from re-infestation by ticks.

Two antifeedants, isopongaflavone and tephrosin have been isolated from Tephrosia elata. Tephrosin displayed high activity against Spodoptera exempta, while isopongaflavone was shown to be very active against Maruca testulalis and Eldana saccharina. Rotenone was found to be active as an antifeedant against S. exempta, E. saccharina and M. testulalis. Insects in the orders Coleoptera, Hymenoptera, Lepidoptera and Diptera, all associated with T. elata seed pods, were identified.