Dietary supplement using cockroach meal: impact on growth indices and biochemical responses in hybrid catfish

Globally the need to substitute fishmeal with other animal protein sources in the fish diet has gained more attention; which is occasioned by the increasing cost of fish. A 12-week trial was conducted to ascertain the growth indices and biochemical response of hybrid catfish (Clarias gariepinus(♀) and Heterobranchus bidorsalis (♂)) fed cockroach meal supplement. A total of 800 hybrid catfish were randomly distributed into four dietary treatments (Diet A- control feed), Diet B (50 % cockroach and 50 % fishmeal), Diet C (100 % cockroach meal) and Diet D (100 % fishmeal). Each treatment was replicated with 35 fish per experimental pond in a completely randomized design. Progressive weight gain was determined bi-weekly. At the end of the study period, fishes were randomly sacrificed for proximate compositions and plasma biochemical analyses (glucose, triglyceride, cholesterol, total protein, albumin) using standard protocols. The study revealed that growth parameters (Weight gain, Average weight gain, Protein efficiency ratio, Feed Conversion rate, Specific growth rate and Survival rate (SR) were influenced by the dietary treatments (p>0.05). The highest weight gain was recorded in Diet 1 (8847.73±292.65 g) > Diet 2 (7816.33±121.71 g)>Diet 3 (7811.67±566.08 g) >Diet 4 (7022.00±44.193 g). Similarly, the best feed conversion ratio was found in fish fed Diet A (10.12±0.01),>Diet B, C and D had the same values of 0.11 g respectively. There was no significant (p>0.05) difference in plasma biochemical indicators measured when compared to the control (Diet A). Thus, indicating that all the fish were healthy and had normal physiological activities. Cockroach meal can therefore, be used as a feed supplement without having any adverse effect on the growth and well-being of hybrid catfish fingerling

Bacteria and fungi analyses of fish diets with grasshopper and cockroach meals: the potential replacement of fishmeal in fish diets

The need to further ascertain the quality of fishmeal with biological indicators has poised this study to determine the biological characterisation of formulated diets with supplemented insect protein (variegated grasshopper and American cockroach). The diets (A–F) were prepared with local ingredients (A, 100% grasshopper meal; B, 100% fishmeal; C, 1:1 grasshopper:fishmeal; D, 1:1 cockroach:fishmeal; E, 100% cockroach meal; F, commercial diet). Samples of prepared diets ready to be stored for use were subjected to bacteria and fungi test. Diet F recorded the highest (4.60±1.10×102 cfu g–1) total viable bacteria count. The highest (3.00±0.05×102 cfu g–1) fungi count was recorded in diet A. Six probiotics bacteria were isolated from the diets. Lactobacillus delbrueckii subsp. bulgaricus was only isolated in grasshopper containing diets; as Pediococcus pentosaceus, Bifidobacterium longum, Mycobacterium marinum, Bacillus subtilisand, Lactococcocus lactis were only isolated in diets F, E, D, A and B respectively. Two pathogenic bacteria isolated were Streptoccoci pyogenes and Staphylococcus aureus. Aspergillus flavus and Penicillum sp. are the two species of fungi isolated from diet A, and diets C and E respectively. The diets with insect proteins were rich in probiotic bacteria than other diets may be considered to replace fishmeal in fish diet