No abstract

No abstract

No abstract

The performance of sea‐water reared rainbow trout Oncorhynchus mykiss fed three isonitrogenous and iso‐energetic diets based on either fishmeal, solvent‐extracted soybean meal or yellow lupin (L luteus cv. Wodjil) kernel meal was evaluated. Over the course of a 10‐wk study, the fastest growing fish were those fed the diet containing 50% yellow lupin kernel meal (YLM), which grew from 83.6 ± 0.7 g to 322.8 ± 3.2 g (mean ± SEM). This was not significantly faster than growth of fish fed the diet based on 50% solvent‐extracted soybean meal (SBM), though it was significantly (P < 0.05) faster than the growth of fish fed the fishmeal based diet (FSM). Growth of fish fed the experimental diets was comparable to growth of fish fed a range of commercial diets as a reference. Survival of fish fed the FSM diet was poorest of all the treatments (47.4%), though this was only significantly poorer than that of fish fed the YLM diet (88.9%). Feed intake was highest by fish fed the YLM diet (5.58 g/d) and lowest for fish fed the FSM diet (336 g/d). Reasons for these differences in feed intake were not clear, though they may be related to different levels of buoyancy and palatability among the diets. Feed conversion rate (FCR) was consistent between treatments at about 1.6:1, though given that this study was a sea‐cage based experiment it is likely that considerable unaccounted feed losses occurred, thereby inflating the feed conversion value. Sensory evaluation of fish fed the three test treatments showed no overall difference in the acceptability of the fish, further supporting that solvent‐extracted soybean meal and yellow lupin kernel meal both have considerable potential to replace fishmeal as a protein resource in diets for rainbow trout.

This paper presents a framework for research towards integrating fish production and irrigation systems, focusing on opportunities for poor people as beneficiaries. Any assessment of farming systems in Asia quickly recognizes that 'irrigated' and 'rainfed' zones are far more complex with respect to water availability than such simple terms suggest. The constraints and opportunities for the poor to benefit from integration of fish production into large, institutionally-managed systems are likely to be very different for farmers managing various forms of microirrigation. We categorize irrigation as being under the control of: (1) the household or immediate community; or (2) an outside institution, typically an irrigation authority or department, as the basis of a framework leading to the development of improved systems integrated with fish production for both. We outline approaches that use technical and social methodologies both to understand current systems and to develop innovative approaches in participation with stakeholders. Engineering and management options are examined in an interdisciplinary mode in which action research with local communities follows situation analysis. Projects are being undertaken in India, Pakistan and Sri Lanka but technical and management guidelines, and the wider policy issues developed will have broader relevance in developing countries.