Cultivation of housefly larvae (Musca domestica L.) as a biological method to enrich rice straw and maximise its utilisation

Abstract

This study is aimed at presenting a new biological technique to enrich rice straw via the cultivation of Musca domestica (MD) and at evaluating the outcome of this technique using in vitro and in vivo studies. Rice straw was treated using molasses and water at 17.5: 0.375: 7.0 (w/v/v), respectively. The mixture was left in an open shaded area for 11 successive days to allow MD to lay eggs and produce larvae. During this time, the recorded temperature was 35.6±2.2 °C and the humidity was 49±5.7%. Rice straw treated with 4% urea (URS) and untreated rice straw (RS) were used for comparison with in vitro and in vivo MD maggot rice straw (MRS). The crude protein (CP) and ether extract (EE) contents gradually increased during the first 8 days, and then began to gradually decrease until the 11th day. In vitro studies were performed on RS, MRS and URS as a single substrate. Instead, in the in vivo studies, experimental RS was offered ad libitum to sheep, and a concentrate feed mixture was provided as pellets to cover the maintenance requirements. The volume of produced gas and the in vitro degradability of the organic matter (OM), ash-free neutral detergent fibre, and CP (P<0.05) increased with the fermentation of the mg of MRS, compared to URS, which in turn was (P<0.05) higher than that of RS incubation. The consumed MRS was significantly (P<0.05) higher than the consumed URS. At the same time, the URS consumption was highly (P<0.05) significant, compared to the RS consumption. The eating, ruminating and chewing time (min/head/d) was significantly (P<0.05) higher when RS was consumed, compared to URS and MRS. Eating a diet including MRS led to higher (P<0.05) dry matter, OM, CP, EE, neutral detergent fibre, and acid detergent fibre digestibility, than the diet containing URS, which was significantly (P<0.05) superior to the diet containing RS. The total digestible nutrients (TDN) and digestible crude protein values of the MRS-containing diet improved (P<0.05) more than that of URS, which was significantly (P<0.05) higher than RS. In short, the results indicate that MD maggots could be produced on rice straw to elevate the protein content and nutritional value of feeds. Moreover, this technique improved the feed consumption and digestion coefficients more than the treated and untreated rice straw.