Effect of Aspergillus oryzae on ruminal fermentation, feed intake and dry matter digestibility in cows fed forage-based diets.

The present study was conducted to investigate the effect of Aspergillus oryzae inclusion on ruminal fermentation, feed intake and dry matter (DM) apparent digestibility in cows fed Cenchrus purpureus forage and concentrate. Cows were randomly assigned in a replicated 4 × 4 Latin square design, into four treatments: control and three doses of A. oryzae culture (1, 2 and 3 g/d). Experimental periods had 21 days, in which 14 days were allowed for treatment adaptation and 7 days for sampling. Addition of 2 g/d increased (p = 0.0054) total anaerobic bacteria. For cellulolytic bacteria and fungal populations increases (p < 0.0001) with all doses were observed. Highest concentrations of total short chain fatty acids (SCFAs), acetate, isovalerate and valerate were observed with 2 g/d of additive. Propionate concentration and acetate: propionate (Ac:Pr) ratio were unaffected by treatments. A. oryzae addition did not modify ruminal pH. A decrease of ammonia-N was observed with 2 g/d of additive. Dry matter intake and apparent digestibility of DM were increased (p = 0.0171 and p = 0.0023, respectively) with the fungal culture addition. It is concluded that Aspergillus oryzae strain H/6.28.1 stimulates ruminal fermentation and improves feed intake and dry matter apparent digestibility in cows feeding with Cenchrus purpureus forage and concentrate.

Method of using increasing levels of substitution of the basal diet by test feedstuffs in pig digestibility trials / Metodologia de uso de níveis crescentes de substituição da ração referência pelo alimento teste em ensaios de digestibilidade com suínos

Two experiments were carried out to study the methodology of using increasing levels of substitution of the basal diet with fibrous test feedstuffs (sticky coffee hull - SCH) in digestibility trials with pigs. In Experiment 1, a digestibility trial was conducted using 30 crossbred barrows, allotted in a randomized block design. In Experiment 2, 42 growing and 42 finishing pigs were used, allotted in a completely randomized design, with six diets and seven replicates, with one animal per experimental unit. The six diets consisted of: a control diet, four diets using SCH ME values as obtained in Experiment 1 plus a diet using SCH ME value estimated by linear regression equation for 15% substitution. The digestibility study indicated that the use of increasing levels of substitution (7, 14, 21 and 28%) reduced SCH digestibility. ME values, as-fed basis, were 2,456, 2,377, 2,247 and 1,945kcal/kg. The overall results indicate that higher levels of substitution overestimate the energy value and that the method of increasing levels of substitution of the basal diet with feedstuffs test can be used to more accurately estimate the energy values of fibrous feedstuffs for pigs. For growing and finishing pigs respectively, up to 28% and 15% of sticky coffee hull can be used without impairing pig performance and economic feasibility.

Dois experimentos foram realizados para se estudar a metodologia de uso de porcentagens crescentes de substituição da ração referência pelo alimento teste fibroso (casca de café melosa - CCM), em ensaios de digestibilidade com suínos. No Experimento I, foi realizado um ensaio de digestibilidade utilizando 30 machos castrados, distribuídos em delineamento de blocos ao acaso. No Experimento II, foram utilizados 42 suínos na fase de crescimento e 42 suínos na fase de terminação, distribuídos em delineamento inteiramente ao acaso, com seis rações, sete repetições e um animal por unidade experimental. As seis rações foram: uma ração controle, quatro rações usando os valores de energia metabolizável (EM) da CCM obtidos no Experimento I e uma ração com EM da CCM estimada por equação de regressão linear para 15% de substituição. Os estudos de digestibilidade indicaram que o uso de porcentagens crescentes de substituição - 7, 14, 21 e 28% - reduziu a digestibilidade da CCM. Os valores de EM, na matéria natural, obtidos para a CCM foram 2.456, 2.377, 2.247 e 1.945kcal/kg. Os resultados indicam que porcentagens mais elevadas de substituição superestimam o valor energético e que a crescente substituição da ração referência pelo alimento teste pode ser utilizada para estimar, de forma mais precisa, os valores energéticos de alimentos fibrosos para suínos. Para suínos em crescimento e em terminação, pode-se usar, respectivamente, até 28% e 15% de casca de café melosa sem prejudicar o desempenho e a viabilidade econômica.