Optimizing voluntary intake and utilization of Moringa oleifera leaf meal in Jumbo quail

DSc (Animal Science), North-West University, Mahikeng Campus

Moringa oleifera is nutraceutical plant that possesses antimicrobial, antioxidant, and immune- boosting bioactive compounds with potential to control the growth of pathogenic microorganisms, bolster animal growth performance and enhance meat quality and shelf life. However, antinutritive components including condensed tannins (CT), glycosylates, phytic acid, and fibre restrict the amount of M. oleifera leaf meal (MOLM) that can be included in quail (Coturnix coturnix) diets. Therefore, this thesis aimed to optimize voluntary feed intake and utilization of MOLM in Jumbo quail (Coturnix sp.) using polyethylene glycol (PEG) and exogeneous fibrolytic enzymes. Chapter One provides the background, problem statement, justification, aim and objectives of the thesis. Chapter Two offers an overview of Jumbo quail’s production as well as the nutritional profile and importance of MOLM in quail feeds. It also examines the gaps and contradictions in the available literature on the utility of MOLM in a variety of poultry species. Furthermore, it assesses the effectiveness of several exogenous feed enzymes and tannin-binding agents (including PEG) in ameliorating fibre and CT in feed resources for simple-stomached animals. In Chapter Three, a preliminary feeding trial was conducted using four hundred and thirty-two (432), two-week-old mixed-gender quail chicks (103.4 ± 12.62 g live-weight). The objective was to determine the amount of PEG required to ameliorate CT in MOLM for Jumbo quail based on growth performance, physiology, and meat quality data. Six dietary treatments were designed as follows: a standard grower diet without MOLM (CON); a standard grower diet containing 100 g/kg untreated MOLM (MPG0); and a standard grower diet containing 100 g/kg MOLM pre-treated with PEG at a rate of 2.5 (MPG25), 5 (MPG50), 7.5 (MPG75), and 10 g/kg (MPG100). The chicks were randomly allocated to 36 pens (experimental units), which were replicated six times per dietary treatment. At week 4, significant quadratic trends were recorded for weight gain and feed conversion efficiency (FCE). However, at week 5, FCE linearly declined (P <0.05) as PEG levels increased. Based on the quadratic response (P <0.05) for weight gain, the optimal PEG pre-treatment level was calculated to be 54 g/kg. The purpose of Chapter Four was to investigate the effect of dietary treatments pre-treated with viscozyme® L multi-enzyme (VME) on growth performance, blood parameters, internal organ sizes, carcass, and meat quality characteristics in Jumbo quail. The aim was to use the VME to break down the fibre components of MOLM and subsequently improve its utilisation by the quail. Three hundred and ninety-six (396), two-week-old mixed-gender quail chicks (87.8 ± 4.40 g live-weight) were used. Six dietary treatments were formulated as follows: a standard grower diet without MOLM (CON), a standard grower diet containing 100 g/kg untreated MOLM (VME0); and a standard grower diet containing 100 g/kg MOLM pre-treated with VME at a rate of 2.5 (VME25), 5.0 (VME50), 7.5 (VME75), and 10 g/kg (VME100). In response to incremental amounts of VME, there were no linear or quadratic impacts (P >0.05) on growth performance indicators and carcass features. This suggests that the highest VME treatment rate of 10 g/kg may not have been sufficient to improve feed utilization and positively affect weight gain in Jumbo quail. It was, therefore, determined that higher levels may be needed to improve the utility of MOLM for the Jumbo quail. To simultaneously reduce the harmful effect of fibre and CT, Chapter Five examined the effect of treating MOLM with the optimum PEG concentration (54 g/kg) that was determined in Chapter Three and VME levels beyond the level (10 g/kg) used in Chapter Four. Three hundred and eighty-one (381), one-week-old mix-gender quail chicks (57.5 ± 3.95 g live-weight) were used. Six dietary treatments were formulated as follows: a standard grower diet containing untreated 100 g/kg MOLM (CON); a standard grower diet containing 100 g/kg MOLM pre-treated with 54 g/kg PEG (MPV0); and a standard grower diet containing 100 g/kg MOLM pre-treated with 54 g/kg PEG and 12.5 g/kg (MPV125), 15 g/kg (MPV150), 17.5 g/kg (MPV175) and 20 g/kg (MPV200) of VME. In response to increasing VME levels, there were no linear or quadratic effects (P >0.05) observed for overall feed intake, FCE, haematological, carcass, or meat quality parameters. In week 3, increasing dietary VME levels resulted in a quadratic response (P <0.05) for weight gain. It can be concluded that pre-treatment of MOLM with a combination of PEG and exogenous VME is an ineffective strategy to improve its feed value in diets of Jumbo quail.

Doctoral