ABSTRACT
In Sub-Saharan Africa, Nile tilapia (Oreochromis niloticus L.) make up over 80% of aquaculture production. However, the local aquaculture farmers are restricted by the unavailability and expensive cost of formulated rations. To reduce reliance on the scarce and expensive fishmeal used in fish feeds, alternative insect protein has been successfully utilized in many aquafeeds. However, data on the influence of insect-based feed on the growth and economic benefit of feeding tilapia with the emerging insect-based diet are scanty. This study investigated the effect of partially and completely substituting fishmeal with black soldier fly larval meal (BM) on growth and economic parameters of tilapia. The O. niloticus was fed a standard commercial diet as a control (100% FM; 0% BM), BM33 (67% FM; 33% BM), BM67 (33% FM; 67% BM) and BM100 (0% FM; 100% BM) for 20 weeks in randomly assigned cages mounted in an 800 m2 earthen pond. Results from this study showed that diet type significantly (p < 0.05) affected the feed intake of the fish as well as weight gain. The feed conversion ratio and survival rate of O. niloticus did not vary across the different diets. Fish fed Diet1 had a 15% increase in weight when compared to fish fed the control diet. Return on investment and the cost-benefit ratio was similar across the diets, suggesting that BM is a suitable and cost-equivalent dietary supplement of FM up to 100% in aquafeed for growing tilapia fish in earthen ponds for the market.
ABSTRACT
Nutrient composition of brewers' spent grains (BSG) from two industries and sow and weaner meal (SWM) were different (p < 0.05). In completely randomised design (CRD), thirty (30) Landrace x Pietrain crosses 35 to 40 ± 5 kg were randomly allocated to 10 pens each with 3 pigs based on the initial weight. Five diets were assigned to pig, where BSG replaced SWM at 0% (T1), 25% (T2), 50% (T3), 75% (T4) and 100% (T5) on DM basis. Daily feed intake and weekly live weight, feed conversion ratio (FCR) and the net profit were recorded for 42 days. Feed intake increased from T1-T3 and then decreased (p < 0.05). The average daily gains (ADG) were different (p < 0.05), but T1 to T3 were similar (p > 0.05). FCR was similar (p > 0.05) from T1 to T3 but different for T4 and T5 (p < 0.05). Feed cost decreased with the increase in BSG levels. The net return was highest in T3 (50% BSG) than in T1 and T2 but lower in T5. It was concluded that BSG can replace 50% SWM in grower pigs' diets without adverse effect on daily gain with good economic returns.
