Browsing by Author "Dreyer, Stephanie"
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- ItemAn evaluation on the effects of three different dietary emulsifiers and the use of black soldier fly (Hermetia illucens) larvae oil on young broiler production(Stellenbosch : Stellenbosch University, 2021-04) Dreyer, Stephanie; Pieterse, Elsje; Hoffman, Louwrens C.; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences.ENGLISH ABSTRACT: The aim of the study was to investigate the use of black soldier fly (Hermetia Illucens larvae) oil and three dietary emulsifiers in broiler diets. The first part of the study determined the production parameters; organ and intestinal parameters, carcass yield and the physical meat quality of broilers. The broilers received five treatments fed in all three phases (starter, grower and finisher). The treatments consisted of sunflower oil (SF) as the control, black soldier fly larvae oil (LO) without an emulsifier and black soldier fly larvae oil with the different emulsifiers. Three different emulsifiers used consisted of Excential energy plus (EEP) at 250g/ton, Lesitol (LES) at 0.2L/ton and Lysoforte (LYS) at 250g/ton. A total of 300 broilers were used for this study and were grouped and assigned to one of the five diets for 32 days. No significant differences in the growth rate, weekly feed intake, feed conversion ratio (FCR), average daily gain (ADG), European production efficiency factor (EPEF), protein efficiency factor (PEF) and liveability where found between the different treatments. These results indicate that LO could perform on the same level as SF and could replace SF in broiler production. This finding is further demonstrated in the ability of broilers to utilise LO without the help of an emulsifier (no improvement were seen with the use of an emulsifier). No significant differences in the broiler carcass yields (dressing percentage, breast component), nor on their physical meat quality (pH of the breast and thigh and on breast colour) were found between the different treatments. This suggests that the use of LO had no negative effect on these parameters when compared to LO. Furthermore, the lack of differences found between LO with EEP, LES and LYS further demonstrates the ability of broilers to utilise LO efficiently. No significant differences in the organ weight and organ to body percentage of the gizzard, liver, spleen and heart of broilers were found between the different treatments. However, the use of LO showed to have an effect on the bursa of Fabricius size. Broilers receiving LO showed heavier bursa of Fabricius weights when compared to SF and LES. An increase in bursal weight in disease free birds is correlated with an improvement in immune cell production. Therefore, the use of LO in the diet of broilers is able to improve the immune system of birds. Furthermore, the bursa weights of all the treatments still fall within the range that is considered as normal. This indicates that none of the emulsifiers used in the study had a negative effect on the bursa weight. None of the emulsifiers and the use of LO had an effect on the pH of the duodenum, ileum and caeca. However, LES had an effect on gizzard and jejunum pH which may be related to its possible effects on digestion retention time in the gizzard causing a decrease in gizzard pH.This in turn could influence the amount of duodenal secretions needed to buffer against the acidic content (increase in pH) when it enters the intestines. Despite these differences, the pH of the gizzard and jejunum for treatment LES still fell within the normal pH range for both these organs. Significant differences were found in the liver lightness (L ̽) between LO with EEP and LYS. The differences found could be speculated based on the interaction of emulsifier type and lipid source on lipogenesis in the body. No significant differences in the gizzard scores were found with the use of the different emulsifiers (at standard and double the standard inclusion level) and LO which suggests that none of the treatments contained any substance that could have negatively affected gizzard health. The second part of the study determined the digestibility parameters of broilers for crude protein (CP), crude lipid (EE), ash and the apparent metabolizable energy (AME) of the diet. In this study, broilers received the same treatments as described in the first part of the study. A total of a hundred and twenty Cobb 500 broiler chickens were used in the trial. The birds were first acclimatized to a standard control diet for four days (adaption period) after which they were individually weighed and randomly assigned to one of the five treatments. None of the emulsifiers and the use of LO had an effect on the coefficient of total tract digestibility (CTTD) of crude protein, crude lipid and ash. This could suggest that the use of EEP, LES, LYS and LO had no negative effect on the utilization of crude protein, crude lipid and ash by broilers. Therefore, all five treatments performed on the same level. However, EEP negatively affected the apparent metabolizable energy (AME); whereas LES and LYS had no effect on AME. This could suggest that LO is able to be utilised efficiently by broilers without the help of an emulsifier and performed better than SF and therefore could improve the performance of broilers. In terms of crude fibre (CF), no significant differences were found between LO and SF indicating that LO performed on the same level as SF and could be utilised in broiler production without having a negative effect on crude fibre utilization. Significant differences were found between LO with EEP and LYS. The use of LYS showed to have improved CF digestibility whereas EEP reduced it. Furthermore, Emulsifier EEP was the only emulsifier that different significantly from SF and was the least effective treatment at improving CF utilization by broilers. This could therefore, suggest that emulsifier type could affect crude fibre utilization. Overall, the study indicated that the use of emulsifiers with LO in the diet of young broilers may have an effect on organ and intestinal pH, thigh colour, crude fibre and AME digestibility. Whereas, the use of LO have shown to have no side effects on normal broiler production), meat quality traits, gizzard health and on nutrient utilization when compared to SF. This indicates that LO could be seen as a promising alternative to sunflower oil in broiler production. The use of the different emulsifiers in the diet showed no negative effect or improvement on broiler production, organ and intestinal pH but may have had an effect on thigh colour, crude fibre and AME digestibility. Therefore the use of an emulsifier and fat type could have an effect on broiler production parameters.