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Accueil du site → Master → Afrique du Sud → 2018 → The evaluation of locally produced full-fat canola seed (Brassica napus) as an alternative protein source in the diets of slaughter ostriches (Struthio camelus var. domesticus)

Stellenbosch University (2018)

The evaluation of locally produced full-fat canola seed (Brassica napus) as an alternative protein source in the diets of slaughter ostriches (Struthio camelus var. domesticus)

Niemann, Gert Jacobus

Titre : The evaluation of locally produced full-fat canola seed (Brassica napus) as an alternative protein source in the diets of slaughter ostriches (Struthio camelus var. domesticus)

Auteur : Niemann, Gert Jacobus

Université de soutenance : Stellenbosch University

Grade : Master of Science (MS) 2018

Résumé partiel
Ostriches are multi-purpose animals, producing feathers, leather and meat that contribute to the income generated from slaughter ostrich production. Compared to other domesticated farm animals, knowledge of the nutritional requirements of ostriches has been very limited, until recently. Together with simulation models this knowledge gained is being used to formulate least cost, nutrient specific rations for ostriches in different production phases. In an effort to reduce feeding costs, which make up the largest expense (ca. 75%) in an intensive ostrich production unit, the use of alternative protein sources are being explored to replace the more expensive protein sources that make up a large portion of the diet. Full-fat canola seed (FFCS) is one such locally produced protein source that has the potential to replace current protein sources such as soybean oilcake meal. However, it is unclear whether ostriches will readily consume canola, due to its anti-nutritional factors, and what effect its consumption may have on animal performance. The feeding preference (Chapter 3) of ostriches towards canola was established by placing 60 South African Black ostriches (82.2 ± 1.06 kg in live weight, 233 days of age) in ten camps of six birds per camp. Each camp had five identical feed troughs, each containing diets, where FFCS incrementally (0, 25, 50%, 75 and 100% of protein source) replaced the soybean oilcake meal (9.8% of the total diet composition in control diet) as protein source. Feed and water were made available ad libitum. Dry matter intake (DMI) was measured on a daily basis and feed colour characteristics were measured based on CIE L*, a* and b* colour attributes. Only the 25%FFCS (25% soybean oilcake meal replacement diet) showed a higher DMI (817.4 ± 81.98 g/bird/day) than the other diets (average of 488.8 ± 81.98 g/bird/day). While there were slight differences between some of the colour attributes, it is believed to have had no effect on DMI. Based on the results of this study, FFCS can be used to replace 25% soybean oilcake meal without any negative effect on DMI ; resulting in an inclusion level of 6.8% FFCS in ostrich diets. To evaluate to what extent FFCS can be utilised in the diets of slaughter ostriches, 187 day old South African Black ostrich chicks were randomly divided into 15 groups (9 - 12 animals per group). The growth trial (Chapter 4)commenced at the onset of the starter phase when the chicks were 84 days of age weighing 24.7 ± 0.36kg. Five iso-nutritional treatment diets with varying levels of FFCS were randomly allocated to the groups with three replications per treatment diet. Birds were reared according to standard practises and slaughtered at 309 days of age (93.2 ± 1.82 kg). Within each feeding phase, FFCS incrementally (0%, 25%, 50%, 75% and 100% of protein source) replaced the soybean oilcake meal as protein source. Feed and water were supplied ad libitum. Dry matter intake, average daily gain (ADG), feed conversion ratio (FCR) and end weights were recorded with in each phase and over the entire trial period, as well as slaughter traits. No differences were observed regarding production traits during the starter and finisher phases. Dry matter intake during the grower phase was lowest (P =0.01) for the 100% replacement of soybean oilcake meal (100%FFCS) (1.52 kg/bird/day). The rest of the diets with an average DMI of 1.80 kg /bird/day did not differ. The 100%FFCS also showed the slowest growth (P =0.01) (152.0 g/bird/day) during the grower phase, and did not differ from 25%FFCS (208.9 g/bird/day) and 75%FFCS (209.5 g/bird/day) diets. With the 0%FFCS (236.2 g/bird/day) and 50%FFCS (267.8 g/bird/day) diets resulting in higher ADG. End weights during the grower phase for the 0%FFCS, 25%FFCS, 50%FFCS and 75%FFCS (74.8, 72.2, 76.8 and 72.5 kg respectively) did not differ from each other. The 100%FFCS resulted in lower end weights (67.4 kg), although not differing from the 25%FFCS and 75%FFCS. For the overall trial period the only differences observed, were within ADG, with the 0%FFCS, 50%FFCS and 75%FFCS replacement diets showing the fastest growth and the 100%FFCS, although not differing from the 25%FFCS and 75%FFCS diets, resulted in the slowest growth. Fat pad weight was the only slaughter trait that revealed differences between diets, with the 50%FFCS resulting in the heaviest fat pad weights. Based on these results, it is recommended that a maximum of 20.6% inclusion (75%FFCS) of FFCS be used in diets during the grower phase as it may lead to reduced performance when exceeded. Although in the other phases, FFCS can be included up to the maximum levels evaluated (100% replacement of soybean oilcake meal) without any detrimental effects. The aim of the study in Chapter 5 was to evaluate the effect of different dietary FFCS inclusion levels on the feathers, leather an

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