ABATTOIR SLUDGE AS SUBSTRATE FOR BIOMASS PRODUCTIVITY OF BLACK SOLDIER FLY LARVAE
Loading...
Date
2022-01-02
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
COLLEGE OF VETERINARY AND ANIMAL SCIENCES, MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY
Abstract
The study was conducted to assessthe feasibility of using Black Soldier Fly Larvae (BSFL) in the valorization of the abattoir sludge, which is a left - over substance from the effluent treatment plants. The substrate for the study included abattoir sludge as the principal substrate (PS) and hostel food waste as the cosubstrate (Co- S) for BSFL rearing. Two different experiments were carried out to optimize the proportion of principal substrate and co-substrate for rearing larvae, to fix the level of larval incorporation into the substrate and to assess the nutritional qualities of the harvested prepupae. Abattoir sludge without Co-S was the control and treatment included the combinations of principal substrate and the co-substrate in three different proportions (T1: 70 per cent PS and 30 per cent Co-S, T2: 80 per cent PS and 20 per cent Co-S and T3: 90 per cent PS and 10 per cent Co-S). The efficiency of BSFL to feed on the substrate and get converted into biomass wasevaluated for the control and treatment combinations. The control substrate did not favour the development of larvae. Among the different treatments, T1 had significantly (p<0.001) higher mean prepupal weight (21.04 ± 2.34 milligrams) and total prepupal yield (1.47± 0.14 grams). Therefore, T1 was selected as the best substrate combination for the next stage of experiment. The experiment 2 was conducted to fix the level of larval incorporation in the T1. Larvae were incorporated in four different levels viz., 150 (T4), 450 (T5), 600 (T6) and 750 (T7) mg in the selected substrate combination of the experiment 1. Different treatments did not vary significantly with respect to total prepupal yield, feed conversion and reduction efficiencies. The average prepupal weight (38.44 ± 6.34 milligrams) and larval survivability (82.67 ± 7.04 per cent) were observed to be highest for T4. Therefore, T4 was selected as the best treatment. The protein content of larvae harvested from different treatments ranged from 29.88 ± 0.93 to 34.77 ± 2.62 per cent. The fat content was variable and depended on the proportion of co-substrates as well as the level of larval incorporation. The ether extract content ranged from 6.34 ± 2.67 to 18.83 ± 1.00 per cent. The study showed that the nutrients in the abattoir sludge were not readily available to the larvae. Addition of food waste as a co-substrate improved the waste reduction and survival rates of the larvae. Acombination of 70 per cent abattoir sludge and 30 per cent food waste yielded maximum biomass. The optimum amount of BSFL to be added to this substrate combination for the larvae to reach the maximum weight within the shortest development time was found to be 150 mg. However, the utilization of BSFL composting as a method for recycling of untreated abattoir sludge requires further research.