A systematic literature review of the major factors causing yield gap by affecting growth, feed conversion ratio and survival in Nile tilapia (Oreochromis niloticus)

Abstract Productivity among small- and medium-scale tilapia farms varies considerably. The difference between the best performers and lower ones (yield gap), is affected by differences in growth rate and feed conversion ratio (FCR). FCR at the farm level is strongly influenced by survival of fish. In this study a systematic literature review of two databases (ASFA and CAB-Abstracts) identified 1973 potentially relevant articles. Data from 32 articles that met the inclusion criteria were analysed using linear mixed models for the most important factors with significant contributions to growth [investigated through analysis of the thermal growth coefficient (TGC)], survival and FCR of Nile tilapia. Increasing crude protein (CP), dissolved oxygen (DO) and pH significantly decreased FCR and increased TGC. Increasing stocking weight (SW) significantly improved both FCR and survival. Temperature had the largest effect on FCR followed by DO, pH and CP. DO had the largest effect on TGC followed by CP and pH. This study confirms that the optimal rearing temperature for Nile tilapia is between 27 and 32°C. Improving management to optimize DO (> 5 mg/L), stocking density (3–5 fish/m2), SW (> 10 g) and CP (25 − 30%) will improve performance and survival in small- and medium-scale tilapia farming. However, it is hard to influence temperature in ponds and cages while DO is largely influenced by aeration. Since many small- and medium-sized farms do not have aeration, these major tilapia farming systems could benefit from genetically improved strains selected for resilience to highly fluctuating diurnal temperature and DO levels

Fostering bioscience innovation: lessons from BIO-EARN

This paper synthesises the findings of, and distils lessons from a study which has sought to illuminate the process of bioscience innovation in three East African countries: Kenya, Tanzania and Uganda. More specifically, we attempt to trace specific efforts to foster biotechnology innovations in those countries and to determine in what ways and to what extent the innovation system in place impinges on the final outcome of those innovations. The paper concludes with a set of policy recommendations that may enhance bioscience innovations in East Africa

Characterization and conservation of indigenous sheep genetic resources: A practical framework for developing countries

Livestock characterization projects in developing regions are characterized by a mere physical description of traditionally recognized populations or a purely academic genetic description of populations. However, characterization of livestock resources is meant to serve the purpose of developing conservation and utilization programs. A national characterization project should be geared to the specific national livestock production objectives. Thus there is a need to adopt a more practical characterization approach to assist in the development of national conservation and utilization strategies. This report provides a practical methodological framework suited for characterization and conservation of sheep resources in developing regions. The report highlights current approaches and tools for characterization and conservation of sheep resources and presents a model approach synthesising results of a study on characterization and conservation of sheep resources of Ethiopia. The study is a collaborative project between Wageningen University and the International Livestock Research Institute. The methodological framework can be applied elsewhere in developing countries with similar characterization and conservation objectives. This report largely dwelt on the technical aspects of sheep genetic resource characterization and conservation in developing regions. Operational aspects of setting up national programs for characterization and conservation action may be country specific. However, some general aspects such as institutional setups and breeding policy and strategy formulation could be similar across countries. A proposed scheme for setting up a national livestock characterization and conservation program is presented, taking Ethiopia as a case study