The aim of this article was to evaluate the in vivo mechanism of action through which ractopamine reduces the amount of adipose tissue in carcass of animals fed diets supplemented with this drug. Literature search was carried out, using the keywords Ractopamine, lipogenesis, lipolysis, fatty acid and adipose tissue. The scoring system was designed for the adequacy of the methodology. A total of eight papers were found-all published in the English language. The determination of lipolysis and lipogenesis was carried out using different methods-from the quantification of non-esterified fatty acids in the blood to molecular analyses of adipose tissue. The review analysis suggested that, at least in the pigs, the use of this drug reduced lipid deposition in the carcass due to a greater inhibition of lipogenesis than an increase in lipolysis.

We investigated the effects of beta-glucans (Saccharomyces cerevisiae) ingestion on metabolic parameters of Wistar rats receiving high-fat diet. The experimental period was divided into two stages: in the first one, the animals were divided into two groups containing 12 animals each. The first group received commercial feed and the second received high-fat diet containing 20% of pork fat during 60 days. At the end of this period, body weight, blood glucose and Lee index were assessed. In the second stage, those 24 animals were redivided into four groups: (C) - control diet; (CB) - control diet and treated with Beta-glucan (BG); (O) - obese animals and (OB) - obese animals treated with BG. Animals from groups CB and OB received 30 mg/kg of BG dissolved in saline solution by gavage. Animals from groups C and O received only saline solution for 28 days. The design used was totally randomized in 2 × 2 factorial scheme. Data were submitted to analysis of variance (anova). Animals from OB group showed inferior levels (p < 0.05) of total cholesterol (13.33%), triacylglycerols (16.77%) and blood glucose (23.97%) when compared to the animals from group O. The use of BG has provided smaller increase in Lee index (p < 0.05), without promoting alteration in feed and water consumption, organs weight, HDL-C, LDL+VLDL-C, carcass composition, villus/crypt ratio, and pancreas, kidney and stomach histology. BG from S. cerevisiae promoted beneficial metabolic effects in rats receiving high-fat diet.

SummaryThe use of medium-chain triglycerides (MCTs) has been studied for years in an attempt to elucidate their effects in food intake and body weight in animals. The aim of this study was to determine whether there is evidence that the use of MCT reduces consumption and body weight gain in rats, a species chosen as it has been widely used as an animal model in different surveys. A search of scientific work was performed in November 2011 on two bases: 'Web of Science' and 'PubMed'. The terms sample size and homogeneity, randomisation, food consumption and weight gain, body composition, enzyme activity and hormonal activity in rats were used as selection criteria. Thirteen papers were selected after the refinement of the research. Twelve studies measured weight gain and among these, seven detected a decrease in weight gain and five found no differences. Twelve papers also measured food intake and among these, four detected a decrease in consumption, one detected an increase and seven found no differences. Based on established criteria for the ranking of scientific papers, it is concluded that there is strong evidence that MCTs can effectively reduce the consumption and subsequent weight gain of animals. However, in the long term, there may not be differences in results depending on the phenotypic adaptation of animals to a new metabolic condition.

The objective of this study was to evaluate the addition of IGF-I to pig insemination doses stored at 158C, in conjunction with the addition of different amounts of vitamin E (a-tocopherol). Semen samples (n 5 12) from four boars were treated by the addition of different concentrations of vitamin E, ranging up to 400 mg/ml. Immediately after processing and after the doses had been stored at 158C for 24 or 72 h, samples were warmed at 378C and 30 ng/ml of IGF-I was added. The assessments were made after 10 and 120 min of IGF-I addition. There was a minor effect of the vitamin E added before cooling and IGF-I added after storage on sperm quality. The addition of 400 mg/ml of vitamin E to diluted semen reduced ( P , 0.01) the malondialdehyde (MDA) production in boar semen stored at 158C for 72 h, regardless of the addition of IGF-I as additive during a 120 min incubation period at 378C. In these conditions, IGF-I also reduced ( P , 0.05) the MDA production in semen samples without addition of vitamin E. IGF-I in the presence of vitamin E reduced ( P 5 0.03) the glucose intake in freshly diluted boar semen samples before cooling. It was concluded that the addition of 400 mg/ml of vitamin E reduces the MDA production in boar semen stored at 158C for 72 h, regardless of the presence of IGF-I additive. The addition of IGF-I in doses stored for 72 h with vitamin E ensures higher sperm motility after 120 min of incubation at 378C.

Objetivou-se avaliar a composição química, vitreosidade e valores nutricionais de diferentes híbridos de milho através de análises laboratoriais e de um ensaio de metabolismo com suínos em crescimento. Foram utilizados 24 suínos em fase de crescimento (35,6 Kg ±± 3,05 kg de PV) machos castrados mestiços (LD x LW), os quais foram mantidos em gaiolas de metabolismo e distribuídos em um delineamento inteiramente ao acaso totalizando 24 parcelas. Os tratamentos experimentais consistiram de 6 rações com os seguintes híbridos de milho: milho óleo (Móleo), milho QPM (MQPM), milho dentado (Mdent), milho semidentado (Msemi) e dois milhos duros (Mdur1) e (Mdur2). Os valores obtidos de vitreosidade, coeficiente de digestibilidade da proteína bruta (CDPB) e energia digestível (ED) para Móleo, MQPM, Mdent, Msemi, Mdur1 e Mdur2 foram 78,5%; 71,7%; 57,2%; 68,2%; 75,9%; 82,8%; 81,68%; 80,14%; 82,35%; 69,71%; 76,98%; 75,61%; 3680; 3426; 3597; 3441; 3340 e 3469 Kcal/Kg, respectivamente. Foram observadas diferenças significativas (P<0,05) para os valores de vitreosidade, mostrando que os milhos de textura dura apresentam maior vitreosidade em relação ao semidentado e ao dentado. Houve diferenças significativas no CDMS, CDPB e ED entre os milhos estudados (P<0,05), mostrando que o milho óleo (Móleo) e o dentado (Mdent) foram superiores aos demais. Em relação ao nitrogênio retido (%NR), houve diferenças significativas (P<0,05) entre os milhos estudados. Para esta variável os milhos dentado, QPM e alto óleo mostraram-se superiores aos milhos semidentado e os duros. Conclui-se que os milhos dentado, Móleo e MQPM foram superiores aos demais.