Lipid metabolism, fatty acid composition and meat quality in broilers supplemented with increasing levels of defrosted black soldier fly larvae

A feeding experiment was conducted to investigate the impact of feeding defrosted whole black soldier fly larvae (BSFL) to broilers in increasing levels in the ration on blood metabolites, carcass characteristics (CC) and on changes in fatty acid (FA) composition in plasma, muscle and abdominal fat. Day-old chicks (Ross-308; n=252) were assigned to one of four groups each with 6 replicate pens (10-11 birds/pen). The birds were fed either a demand-oriented age-specific control (CON) diet and had no access to BSFL, or fed CON plus BSFL at 10% (L10), 20% (L20) or 30% (L30) of CON feed intake. At weeks (wk) 4 and 6, birds (2 per pen) were slaughtered to collect blood, breast muscle, and abdominal fat samples and to determine CC. Plasma triglyceride concentrations increased in a dose dependent manner with increasing levels of whole BSFL compared with CON (P<0.05). The L30 and L20 had higher plasma non-esterified FA concentrations than CON (P<0.05). There were no differences in slaughter weight and CC between groups (P>0.05). Broilers fed 30% BSFL had the highest saturated FA proportion in plasma, muscle and abdominal fat and the lowest monounsaturated FA proportion in abdominal fat tissue (P<0.05). The levels of total polyunsaturated FA in plasma and abdominal fat were lower in L30 than in CON (P<0.05). In plasma, muscle and abdominal fat, the proportion of conjugated linoleic acid (isomer C18:2cis-9, trans-11) was highest in L30 followed by L20 and L10 compared with CON (P<0.05). Overall, whole BSFL could be included in broiler diets up to 20% to promote sustainability in broiler farming without adverse effects on slaughter weight, meat quality and FA compositions, whereas, the highest inclusion level (i.e. 30%) of whole BSFL in the daily ration was associated with altered FA composition in plasma, fat and meat.