Insect meal (Hermetia illucens) as an alternative protein source for Jumbo quails : physiological and meat quality traits

Abstract

Globally, soybean (Glycine max) meal is used as a standard vegetable protein source for poultry feeds. However, due to the negative ecological impact of soybean production, alternative natural and inexpensive protein sources such as insect meals ought to be identified and evaluated. Recently, there has been a substantial growth in the use of insect meal as a viable and sustainable alternative protein source for a number of meat animals but not in Jumbo quails ( Coturnix coturnix). Insects are generally easy to rear, have a small carbon footprint and contain a high level of protein and essential amino acids. Therefore, the present study was conducted to determine the effect of partially replacing soya products with Black soldier fly (Hermetia illucens) larvae (BSFL) meal on feed intake, growth performance, haemato-biochemistry, internal organs, and carcass and meat quality traits of Jumbo quails. For a period of four weeks, 315, two-week-old, mixed gender Jumbo quails (53.79 ± 5.193 g live-weight) were fed five isonitrogenous and isoenergetic experimental diets, which were randomly allocated to 35 pens. The BSFL meal was included at a rate of 0, 25, 50, 75 and 100 g/kg (BSFL0, BSFL25, BSFL50, BSFL75 and BSFLlO0, respectively) as a replacement for soya products. The birds had access to the dietary treatments and water ad libitum. Infrared lights were placed in the pens to provide warmth as the trial was conducted during the winter season. Average weekly gain-to-feed ratio (G:F) was calculated using average weekly feed intake (A WFI) and average weekly body weight gain (ABWG) measured during the feeding trial. The birds were slaughtered at six weeks of age at a local abattoir. During slaughter, blood was collected from two birds that were randomly selected per pen. Repeated measures analysis showed a significant diet x week interaction on G:F. In weeks 3 and 5, there were linear trends for G:F in response to the inclusion level of BSFL meal. There were quadratic trends for overall feed intake [y = 605 (±17.56) + 2.1 (±0.82)x - 0.02 (±0.0077)x2 ; R2 = 0.20; P = 0.023] and overall weight gain [y= 155 (±4.70) + 0.57 (±0.22)x - 0.0049

(±0.002)x2 ; R2 = 0.22; P = 0.03]. Using the quadratic equation for overall weight gain, the optimal inclusion level for the BSFL meal was calculated to be 54 g/kg. There were no significant linear or quadratic trends for all haematological and serum biochemical parameters with the exception of albumin-to-globulin (ALB/GLOB) ratio in response to BSFL levels. Similarly, there were neither significant linear nor quadratic trends for size of internal organs except for gizzards, which linearly increased [y = 0.05 (±0.004) x + 2.3 (±0.085); R2 = 0.18; P = 0.04] with BSFL levels. Quadratic trends were observed for size of large intestine [y = 1.4 (±0.077) + 0.0074 (±0.0036) x - 0.000073 (±0.0000337) x2 ; R2 = 0.16; P = 0.04] and breast weight [y = 21.9 (±0.637) + 0.054 (±0.0299)x - 0.00058 (±0.000278)x2 ; R2 = 0.168; P = 0.046]in response to BSFL levels. For all the meat quality parameters, there were neither linear nor quadratic (P>0.05) effects. There were no significant (P >0.05) differences on feed intake, physiological and meat quality responses across all dietary treatments. It was concluded that the inclusion of BSFL meal at the rate of 54 g/kg maximized weight gain in Jumbo quails without compromising any other traits of economic importance. These findings prove that BSFL meal at 54 g/kg is a viable, sustainable, low cost partial alternative to soybean protein for Jumbo quails.