Substituição do milho pelo sorgo sobre o desempenho zootécnico e na digestibilidade em coelhos / Replacement of corn by sorghum on zootechnical performance and digestibility in rabbits

O milho é a principal fonte de energia nas dietas animais. Em algumas regiões brasileiras, sua disponibilidade, principalmente na entressafra, é insuficiente para atender à demanda, fazendo com que seu preço se eleve. Neste estudo, objetivou-se avaliar a substituição do milho pelo sorgo sobre o desempenho zootécnico e a digestibilidade em coelhos. Foram utilizados 60 animais machos da raça Nova Zelândia Branco, divididos em três tratamentos: ração base milho (TM); ração base sorgo (TS) e ração base 50% de milho + 50% de sorgo (TMS). No ensaio de desempenho, avaliou-se ganho de peso (GP), consumo de ração (CR), conversão alimentar (CA), coeficientes de digestibilidade da matéria seca (CDMS), proteína bruta (CDPB), fibra em detergente neutro (CDFDN) e fibra em detergente ácido (CDFDA). Observou-se que o CRM, a CA e o GPM não foram afetados pela substituição do milho pelo sorgo, nos níveis de 50% e 100%. Os resultados de digestibilidade demonstraram maiores CDPB e CDFDN na ração base milho, não havendo diferenças entre os demais parâmetros estudados. O sorgo com baixo teor de tanino pode ser usado nas rações de crescimento de coelhos em níveis de substituição de 50% ou 100% da participação do milho, sem prejuízos para o desempenho zootécnico e a digestibilidade.(AU)

Corn is the main source of energy in animal diets. In some Brazilian regions, its availability, especially in the off-season, may be insufficient to meet demand, which causes prices to increase. In this context, the aim of this study was to evaluate the substitution of maize by sorghum on the performance and digestibility of rabbits. Sixty New Zealand White bucks were used, divided in three treatments, maize base ration (TM); based on grain sorghum ration (TS) and base ration 50% corn + 50% sorghum grain (TMS). In the performance test, weight gain (GP), feed intake (CR) and feed conversion ratio (CA) were evaluated. In the digestibility assay, 21 animals were used. The total dry matter (CDMS), crude protein (CDPB), gross energy (EB), neutral detergent fiber (CDFDN) and acid detergent fiber (CDFDA) coefficients were evaluated. There was no significant difference for any of the performance parameters studied (P > 0.05). The digestibility results showed higher CDPB and CDFDN in the corn diet (P <0.05), with no differences between the other parameters studied. Low tannin sorghum can be used in rabbit growth diets at substitution levels of 50% or 100% of maize participation without impairing zootechnical performance and digestibility.(AU)

A role for transforming growth factor-beta apoptotic signaling pathway in liver injury induced by ingestion of water contaminated with high levels of Cr(VI).

Hexavalent chromium [Cr(VI)] exposure is commonly associated with lung cancer. Although other adverse health effects have been reported, some authors, on assuming that orally ingested Cr(VI) is efficiently detoxified upon reduction by body fluids, believe that Cr(VI) do not target cells other than respiratory tract cells. In rodents, ingested Cr(VI)-contaminated water was reported to induce, in the liver, increases in TGF-beta transcripts. As TGF-beta dependent signaling pathways are closely associated with hepatic injury, the present study was undertaken addressing two specific issues: the effects of ingestion of water contaminated with high levels of Cr(VI) in rat liver structure and function; and the role of the TGF-beta pathway in Cr(VI)-induced liver injury. Examination of Wistar rats exposed to 20 ppm Cr(VI)-contaminated water for 10 weeks showed increased serum glucose and alanine aminotransferase (ALT) levels. Liver histological examination revealed hepatocellular apoptosis, further confirmed by immunohystochemical study of Caspase 3 expression. Liver gene expression analysis revealed increased expression of Smad2/Smad4 and Dapk, suggesting the involvement of the TGF-beta pathway in the apoptotic process. Since no changes in Smad3 expression were observed it appears apoptosis is using a Smad3-independent pathway. Increased expression of both Caspase 8 and Daxx genes suggests also the involvement of the Fas pathway. Gene expression analysis also revealed that a p160(ROCK)-Rho-independent pathway operates, leading to cell contraction and membrane blebbing, characteristic apoptotic features. These findings suggest that either the amount of Cr(VI) ingested overwhelmed the body fluids reductive capacity or some Cr(VI) escapes the reductive protection barrier, thus targeting the liver and inducing apoptosis.