RESUMO
Dietary exogenous proteases (ENZ) can be used in poultry production to improve the growth of chickens fed low-protein (LP) diets. We hypothesized that ENZ supplemented in an LP diet would improve growth performance and physiological response in broilers for 8-35 days. To investigate this, we used a 2 × 2 factorial design with crude protein (CP, normal diet (NP) and LP) and ENZ. The LP diet contained low in 1% CP and ca. 8-12% amino acids compared to the NP diet and both NP and LP diets were added without or with (1 g/kg of diet) ENZ. We randomly allocated 720 1-week-old Ross 308 male chicks to 48 pens and experimental diets. At 21 days, dietary ENZ, but not CP, increased (p = 0.007) live body weight. Body weight gain from 8-21 days was affected (p = 0.006) by dietary ENZ, but was not affected (p = 0.210) by CP. The feed conversion ratio was affected by both CP and ENZ during the starter period (p < 0.05), by ENZ (p = 0.034) during the finisher period, and by CP (p < 0.001) during the whole period. However, the interaction between CP and ENZ did not significantly affect growth performance (p > 0.05). Dietary ENZ increased (p = 0.013) the relative weight of liver at 21 days. CP and ENZ affected (p = 0.043) total short-chain fatty acids at 21 days. However, this effect was not seen (p = 0.888) at 35 days. Dietary CP increased (p < 0.05) the serum concentrations of both uric acid and creatinine in broilers. We concluded that dietary ENZ is more beneficial to younger broilers, independent of CP levels, and that its effect was restricted to body weight and the feed conversion ratio.
RESUMO
A survey involving 120 small-scale dairy farmers was carried out to assess risk factors associated with brucellosis in cattle from selected sectors of Nyagatare District, Rwanda. A sample of cattle from nine selected sectors of Nyagatare was tested for brucellosis using the Rose Bengal Test. Of the respondents, 57.5% were unaware of brucellosis as a disease, 85.8% did not screen new additions to the herd for brucellosis and 82.5% did not remove brucellosis seropositive animals from the herd. The prevalence of brucellosis in herds with cows with no history of abortion was 38.5% and 17.0% in those with a history of abortion. None of the respondents disinfected abortion sites or vaccinated against brucellosis. The prevalence of brucellosis in cows with a history of retained placenta was 36% and 2% in those with no history of retained placenta. Of the respondents, 62.5% reportedly fed foetal membranes to dogs. About 65.8% of the respondents with brucellosis-positive animals reported a calving interval longer than 1 year. Katabagemu (28.6%) had the highest prevalence of brucellosis seropositivity while Karama had none. Brucellosis in cows (21.4%) was significantly higher than that in heifers (12.8%) (p < 0.05), but there was no significant difference between heifers and bulls or between bulls and cows (p > 0.05). The occurrence of brucellosis in herds with 40-70 cattle (26.9%) was significantly greater than the 14.9% of herds with 10-39 cattle (p < 0.05). Seropositivity to brucellosis in cross-breed cattle (23.6%) was significantly greater than that in indigenous cattle (13.8%) (p < 0.05). There was no significant difference in the overall prevalence of brucellosis in cattle from different grazing systems (p > 0.05). Seropositivity to brucellosis was significantly different (p < 0.05) between the fourth parity (32.5%) and first parity (14.3%) cows. The findings in this study confirmed the existence of brucellosis as a problem in Nyagatare and the authors recommend that farmer education on the epidemiology, risk factors and mitigation of the disease be undertaken as a matter of urgency.