The effects of different dietary energy and protein concentrations on the digestive anatomy of ostriches

Diets with three energy concentrations and five protein concentrations, structured in a 3 x 5 factorial experimental design, were formulated for the pre-starter (2 – 10 kg), starter (10 – 30 kg), grower (30 – 60 kg) and finisher phases (60 – 80 kg) of slaughter ostriches. These diets were fed to 15 separate groups of ostriches of six birds each. One of the ostriches per group was slaughtered at 5 kg, 10 kg, 20 kg and 80 kg live weight (45, 75, 100 and 260 days of age, respectively). Two ostriches per group were slaughtered at 40 kg and an average age of 155 days. The different segments of the gastrointestinal tract were measured and weighed to evaluate the effects of varying dietary protein and energy concentrations on digestive anatomy. An increase in dietary energy concentration led to a reduction in the length of the large intestine, small intestine and caeca at the slaughter age of 260 days. The weights of the total intestine and stomach were accordingly affected. This result was probably caused by the higher fibre concentrations of the low energy diets and associated higher bulkiness and longer retention time. Total intestine weight was also increased in birds slaughtered at 80 kg live weight, probably due to fat accumulation in the intestines.