Browsing by Author "Thornhill, Alexander Wallace"

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    Evaluation of a lysophospholipid using two oils on performance, carcass composition and organ characteristics of broilers
    (Stellenbosch : Stellenbosch University, 2020-12) Thornhill, Alexander Wallace; Pieterse, Elsje; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences.
    ENGLISH ABSTRACT: The aim of the study was to investigate the potential to decrease the apparent metabolizable energy (AME) by including a lysophospholipid in the diet of broiler chickens. There were two oils used in the trail: refined soya oil and an unsaturated blend of animal fats and vegetable oils. For each type of oil, three diets were formulated, the first with standard AME and the other two containing 0.25 MJ/kg less. One of the reduced diets included a lysophospholipid, Lysoforte Extend Dry (LEX), at an inclusion level of 500 g/ton. Two thousand, one hundred and twelve chicks were randomly allocated to six treatments, where each treatment was replicated sixteen times. The broiler chickens were raised until slaughter at day 35 of age. Both oils were chemically analysed before diets were formulated, their AME values were calculated using the Wiseman equation corrected for moisture, impurities and unsaponifiables (MIU). Results from the analysis showed that AME values for young broilers, 0-21 days of age, was 36.69 MJ/kg for soya oil and 30.78 MJ/kg for the blended oil, a difference of 5.91 MJ/kg or 16.1% lower. The AME for older birds of ˃ 21 days was 37.66 for soya oil and 33.82 MJ/kg for the blended oil, which was a difference of 3.84 MJ/kg or 10.2% lower. The first phase of the study involved the effect of the decreased AME value and the addition of LEX on broiler production parameters; these parameters included body weight (BW), feed intake (FI), feed conversion ratio (FCR), average daily gain (ADG), protein efficiency ratio (PER) and European production efficiency factor (EPEF). No significant differences were observed for any parameter on soya oil where LEX was added except cumulative FI, while on the blended oil the only parameters that were significantly lower than the control was average BW and a higher FCR. These two parameters of the blended oil were also significantly lower than soya oil with additional LEX. The second part of the trial investigated the effect on the organ and carcass characteristics of broilers. After slaughter the dressing percentage, relative organ weights, relative carcass portion weights and breast muscle pH were measured. No significant differences were observed for any parameter on the relative organ weights of the blended oil treatments, however on the soya oil treatments, significant differences were observed for the gizzard, liver, spleen and the gizzard erosion score. The only significant differences observed between soya oil and the blended oil was the liver and spleen relative weights, of which both was significantly higher on soya oil with additional LEX. On carcass characteristics there were no significant differences observed for any parameter on the blended oil treatments and also between the blended oil and soya oil treatments both with LEX. The only significant difference on soya oil was a lower relative breast weight when LEX was added, no other significant effects were observed for the soya oil treatments. Overall the study indicated that when LEX is added with a decreased dietary energy, there are no adverse effects on normal broiler production parameters, organ or carcass parameters of broilers. This highlights the importance of using LEX in the broiler industry, where reducing dietary energy results in a saving on the feed cost and ultimately results in an increased profitability within the broiler industry.