Substitution of Mukene (Rastreneobola argentea) Protein with Blue bottle fly (Calliphora vomitoria) protein in Nile tilapia (Oreochromis niloticus) diets

Abstract

A feeding trial was conducted at the Aquaculture Research and Development Center, in Kajjansi, Kampala, Uganda, between January 2017 and July 2017, to assess growth performance, feed utilization efficiency and hematology of all-male Oreochromis niloticus fingerlings fed on blue bottle fly meal (BBFM) diets in two different experimental settings. In the first experimental setting, the effect of BBFM diets on growth rate and survival rate was investigated. In the second experiment, the digestibility of BBFM diets and the effect of the diets on hematological condition of the fingerlings were investigated. Oreochromis niloticus fingerlings (1.6 ± 0.9 g) were stocked in five 50 L tanks set in triplicate and fed on 35 % crude protein treatment diets in which blue bottle fly meal (BBFM) replaced fishmeal (FM) at 0% (control), 25%, 50%, 75% and 100% for a period of 12 weeks. In the second experimental setting, all-male O. niloticus fingerlings (12.4 ± 2.1 g) were fed on chromiumoxide incorporated BBFM treatment diets for a period of 12 weeks. Fecal wastes were collected and dried in an oven at 60°c and later analysed for its crude protein, crude lipid content and chromium oxide concentration. Blood samples were collected from three O. niloticus fingerlings in each tank after a period of 30 days and transported on ice to analyze heamatological parameters (Red Blood Cell count, Haemoglobin, Haematocrit, Mean Cell Volume, Mean Cell Haemoglobin Conceteration, Mean Corpsular Haemoglobin, White Blood Cells and differential Leucocyte Counts (monocytes, neutrophils and lymphocytes). Final body mass was significantly different at p<0.05 between the FM diet and the BBFM diets except at the 25% inclusion level. Specific growth rate was significantly different between the FM diet and the BBFM diets except for the 25% inclusion level. There was no significant difference in the Protein efficiency ratios between the FM diet and all the BBFM diets (p=0.091, F=2.719). Feed conversion ratio was not significantly different between the FM diet and the 25%, 50% and 75% diets. The FCR was only different between the FM diet and the 100% BBFM diet (p=0.007). There was no significant difference in the survival of the O. niloticus fingerlings among all the treatment diets (P = 0.206). Apparent digestibility co-efficient (ADC) of crude protein was significantly different across the treatment diets (p<0.05), highest in the FM diet and lowest in the 100% BBFM diet (47.3±3.6 and 18.5±0.5, respectively) p=0.000. Hematological parameters were not significantly different p<0.05 among the treatment diets. It was concluded that replacement of Fish meal with blue bottle fly meal was only practical at the 25% inclusion level.