水産および畜産生産

抽象的な

Effect of Stocking Density and Feed on Growth of Improved (F5) Mono- Sex Oreochromis Shiranus Reared in Tanks

Sanudi F, Jere B, Mzengereza K and Chirwa BB

A study was undertaken to determine the effects of stocking density and type of feed on growth of mono-sex culture of improved strain of Oreochromis shiranus reared in tanks. The fish stocked at 3 fish/m2 and 5 fish/m2 replicated three times were randomly assigned to Malawi Gold Standard (MGS) and maize bran (MB) diets. The fish were cultured for 42 days. Results showed that the mean weight gain and gain in standard length were inversely proportional with stocking density. Treatments fed MGS and a stocking density of 3 fish/m2 had higher mean body weight gain (4.37 ± 0.284 g) and standard length gain (3.07 ± 0.111 cm) compared to 2.60 g and (2.25 ± 0.120 cm) for weigh gain and gain in length for treatments fed MB at 5 fish/m2 respectively. There were significant differences (P<0.001) between treatments fed MGS and MB in terms of mean weight gain and standard body length. The study also determined the rate of survival in the different treatments. The highest survival rate was in MGS and 3 fish/m2 (94.7%) while the least was in MB and 5 fish/m2 (87.1%). This study shows that stocking density and feed affect growth of mono-sex culture of improved strains of O. shiranus reared in tanks. MGS and stocking density of 3 fish/m2 gave the best results. However, for resource limited farmers a recommendation of 3 fish/m2 and MB can be made to achieve 2.59 cm gain in length and 2.78 g gain in weight instead.