Avaliação nutricional do resíduo desidratado de cervejaria para coelhos em crescimento / Nutritional evaluation of dried brewer for growing rabbits

Foi conduzido um ensaio de digestibilidade para determinar o valor nutritivo do resíduo desidratado de cervejaria (RDC) e outro para verificar o desempenho de coelhos em crescimento alimentados com rações contendo diferentes níveis de RDC e a viabilidade econômica da utilização do RDC. No ensaio de digestibilidade, foram utilizados 20 coelhos, de ambos os sexos, da raça Nova Zelândia Branco, com idade média de 45 dias, distribuídos em delineamento experimental inteiramente ao acaso, com dois tratamentos, sendo uma dieta referência e outra dieta teste, na qual o RDC substituiu a ração referência em nível de 30%. Os coeficientes de digestibilidade aparente (CDA) da matéria seca (MS), da energia bruta (EB), da proteína bruta (PB) do RDC foram de 49,97%, 49,34%, e 71,06%, respectivamente, com valores de energia digestível (ED) e proteína digestível (PD) do RDC, com base na matéria seca, de 2330,60kcal/kg e 15,75%. No experimento de desempenho, foram avaliadas rações com níveis de inclusão de RDC de 0%, 5%, 10%, 15%, 20% e 25%. Foram utilizados 120 coelhos da raça Nova Zelândia Branco, 60 machos e 60 fêmeas, com 32 dias de idade, em delineamento experimental inteiramente ao acaso, com seis tratamentos e 10 repetições, sendo a unidade experimental constituída por dois animais. Não foram observadas diferenças no desempenho dos coelhos alimentados com ração contendo níveis crescentes de RDC, exceto para a conversão alimentar aos 70 dias, que apresentou efeito quadrático no período dos 32 aos 70 dias de idade, com a pior conversão alimentar ao nível de 16,95% de RDC. No entanto, houve redução linear nos custos com alimentação, por quilo de ganho de peso dos animais. Conclui-se que o resíduo desidratado de cervejaria apresenta CDA equivalente aos ingredientes convencionais, podendo ser incluído até o nível máximo estudado de 25% nas rações de coelhos em crescimento, sem prejudicar o desempenho.(AU)

Two experiments were conducted, being a digestibility assay in order to determine the nutritive value of dehydrated diets containing different levels of DBR, and the economic viability of the use of DRC brewer residue (DBR) and other assays to verify the performance of growing rabbits fed. In the digestibility experiment, twenty White New Zealand rabbits were used, with an average age of 45 days, of both genders, distributed in a completely randomized design with four treatments, one reference diet and other test diets, in which the DBR replaced the basal diet at 30% level. The apparent digestibility coefficients (ADC) of dry matter (DM), gross energy (GE), crude protein (CP) of DBR were, respectively, 49.97%, 49.34% and 71.06%. The values of digestible energy (DE) and digestible protein (DP) of the DBR, based on dry matter, were 2330.60kcal/kg and 15.75%. In the performance experiment, diets with levels of DBR inclusion of 0%, 5%, 10%, 15%, 20% and 25% were evaluated. One hundred and twenty 32 days old New Zealand White rabbits were used, being 60 males and 60 females, distributed in a completely randomized design with six treatments and ten replicates, and the experimental unit consisted of two animals. No differences (P>0.05) were observed in the performance of rabbits fed diets containing increasing levels of dehydrated brewer residue, except for feed conversion at 70 days which presented a quadratic effect, with the worst results at the level of 16.95% of the DBR inclusion in the diet. It is concluded that the dehydrated brewer residue has good nutritional value and can be included up to the maximum level studied of 25% in the diets of growing rabbits, with no damage to its performance.(AU)

Protective effects of organoselenium compounds against methylmercury-induced oxidative stress in mouse brain mitochondrial-enriched fractions

We evaluated the potential neuroprotective effect of 1-100 µM of four organoselenium compounds: diphenyl diselenide, 3’3-ditri-fluoromethyldiphenyl diselenide, p-methoxy-diphenyl diselenide, and p-chloro-diphenyl diselenide, against methylmercury-induced mitochondrial dysfunction and oxidative stress in mitochondrial-enriched fractions from adult Swiss mouse brain. Methylmercury (10-100 µM) significantly decreased mitochondrial activity, assessed by MTT reduction assay, in a dose-dependent manner, which occurred in parallel with increased glutathione oxidation, hydroperoxide formation (xylenol orange assay) and lipid peroxidation end-products (thiobarbituric acid reactive substances, TBARS). The co-incubation with diphenyl diselenide (100 µM) completely prevented the disruption of mitochondrial activity as well as the increase in TBARS levels caused by methylmercury. The compound 3’3-ditrifluoromethyldiphenyl diselenide provided a partial but significant protection against methylmercury-induced mitochondrial dysfunction (45.4 ± 5.8 percent inhibition of the methylmercury effect). Diphenyl diselenide showed a higher thiol peroxidase activity compared to the other three compounds. Catalase blocked methylmercury-induced TBARS, pointing to hydrogen peroxide as a vector during methylmercury toxicity in this model. This result also suggests that thiol peroxidase activity of organoselenium compounds accounts for their protective actions against methylmercury-induced oxidative stress. Our results show that diphenyl diselenide and potentially other organoselenium compounds may represent important molecules in the search for an improved therapy against the deleterious effects of methylmercury as well as other mercury compounds.