Effect of varying levels of dietary inclusion of sweet lupin on the growth production characteristics of ostriches (Struthio camelus var. domesticus)
Nutrition contributes approximately 75% of the total input costs to an intensive ostrich production unit. An increase in the price of traditional protein sources thus necessitates finding cheaper alternatives. Sweet lupins were identified as a possible alternative; therefore, the effect of feeding various sweet lupin inclusion levels was evaluated throughout the different feeding phases. One hundred and forty ostrich chicks were randomly divided into five dietary treatments with three replications each. The chicks all received a standard commercial pre-starter ostrich diet. Five iso-nutritional diets were formulated for each feeding phase according to specifications set out for each of the different feeding phases using Mixit2+ software. For each feeding phase the diets contained either soybean oilcake meal (control diet, 0LD) or sweet lupins (alternative protein source). The 100 lupin diet (LD) was formulated to include the maximum amount of sweet lupins according to the specifications for the specific species and the feeding phase, and therefore differs between the three feeding phases. Soybean oilcake meal was thus gradually replaced by sweet lupins in the following ratios: 100:0 (0LD), 75:25 (25LD), 50:50 (50LD), 25:75 (75LD), and 0:100 (100LD). Feed and water were supplied ad libitum. Feed intakes and live weights were measured every fortnight until slaughter at ca. 11 months of age. No differences were found between the treatment diets for the live weight, dry matter intake (DMI), average daily gain (ADG) or feed conversion ratio (FCR) at the end of each feeding phase. However, the birds on the 75LD tended to have the highest end weight and ADG, and those on the 100LD the lowest at the end of the starter phase. No differences were found for slaughter weight, dressing percentage and big drum muscle weight of the birds. Birds on the 50LD and 75LD tended to have the heaviest cold carcasses; this differed from the 100LD birds which had the lightest. Birds fed the 50LD had heavier thigh weights than those on the other diets. The results of this study indicate that soybean oilcake meal can be replaced in the diets of slaughter ostriches with sweet lupins up to 15% (75LD) in starter diets and 30% (100LD) in grower and finisher diets without any significant effect on any of the production and slaughter traits.
Keywords: alternative protein, average daily gain, dry matter intake, feed conversion ratio, lupins, ostrich nutrition, production