Effect of feeding regime on growth, digestibility and excretion of purine derivatives in goats

Abstract

A study was conducted to examine the effect o f two dietary regimes on the growth, nutrient digestibility and excretion o f urinary purine derivatives o f cross-bred (nondescriptive x Jamnapari) goats. Fifteen goats (approx 1.5 years old, average body weight 22 ± 1 kg) were fed with an “on farm diet ” consisting o f conventional leaves and coconut poonac for 30 days (27% dry matter, 11.5% crude protein). Thereafter an “experimental ration” (50% conventional leaves + 30% Guinea grass + 20%o coconut poonac & sesame oil meal + mineral mixture) was fed for another 30 days. Feed intake (0.8 ± 0.14 to 1.0 ±0.3 kg/head/day), weight gain (0.33 ± 0.21 to 0.66 ± 0.50 kg/head/day) and dry matter digestibility (50.3 ± 0.56 to 56.8 ± 0.43) increased significantly when the “experimental diet” was fed as compared with the “on farm diet”. Similarly, animals had a higher (P<0.05) excretion o f allantoin and thereby a higher (P<0.05) excretion rate o f total purine derivatives (PD) when fed with the experimental ration. Allantoin from the total PD accounted for more than 75%) while xanthine, hypoxanthine and uric acid accounted for 25%> for both diets. The endogenous mean PD excretion rates ranged from 1.80 and 3.62 mmol/day for “on fa rm ” and “experiemental” diets respectively, which are considered directly related to the ruminal microbial nitrogen production. The results revealed that excretion ofpurine derivatives o f goats are comparable to that o f cattle and sheep. It is important to develop feeding strategies monitored by this technique using locally available feeds, to enhance the performance o f goats