Fontes de lipídios poliinsaturados na nutrição e saúde da tilápia do nilo (oreochromis niloticus)

Pós-graduação em Zootecnia - FMVZ

Influência do tempo de exposição à obesidade sobre a expressão gênica e protéica do sistema regulador do trânsito de cálcio miocárdico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monensina sódica ou anticorpos policlonais contra bactérias precursoras de distúrbios nutricionais em bovinos induzidos à acidose ruminal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influencia do tempo de exposicao a obesidade induzida por dieta hiperlipidica sobre os colagenos tipo I e III miocardico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of food processing and fibre content on the digestibility, energy intake and biochemical parameters of Blue-and-gold macaws (Ara ararauna L. - Aves, Psittacidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estratégias alimentares para a recria e terminação de tourinhos Nelore

Pós-graduação em Zootecnia - FCAV

Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cardiac dysfunction induced by obesity es not related to beta-adrenergic system impairment at the receptor-signalling pathway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acidose ruminal subaguda em ovinos Santa Inês: estudo clínico, laboratorial e avaliação da laminite por termografia infravermelha e radiologia digital

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Carbohydrate- and lipid-enriched meals acutely disrupt glycemic homeostasis by inducing transient insulin resistance in rats

Chronic intake of high-carbohydrate or high-lipid diets is a well-known insulin resistance inducer. This study investigates the immediate effect (1-6 h) of a carbohydrate-or lipid-enriched meal on insulin sensitivity. Fasted rats were refed with standard, carbohydrate-enriched (C), or lipid-enriched (L) meal. Plasma insulin, glucose, and non-esterified fatty acids (NEFA) were measured at 1, 2, 4, and 6 h of refeeding. The glucose-insulin index showed that either carbohydrates or lipids decreased insulin sensitivity at 2 h of refeeding. At this time point, insulin tolerance tests (ITTs) and glucose tolerance tests (GTTs) detected insulin resistance in C rats, while GTT confirmed it in L rats. Reduced glycogen and phosphorylated AKT and GSK3 content revealed hepatic insulin resistance in C rats. Reduced glucose uptake in skeletal muscle subjected to the fatty acid concentration that mimics the high NEFA level of L rats suggests insulin resistance in these animals is mainly in muscle. In conclusion, carbohydrate-or lipid-enriched meals acutely disrupt glycemic homeostasis, inducing a transient insulin resistance, which seems to involve liver and skeletal muscle, respectively. Thus, the insulin resistance observed when those types of diets are chronically consumed may be an evolution of repeated episodes of this transient insulin resistance.

Interaction of dietary vitamin D-3 and sunlight exposure on B. indicus cattle: Animal performance, carcass traits, and meat quality

Attempts to improve beef tenderness through supplementation with dietary vitamin D-3 have been challenged by null results and negative impacts on animal performance and carcass traits. Because vitamin D-3 is also synthesised by the animal via ultraviolet radiation from sunlight, the effectiveness of supplementation with dietary vitamin D-3 may be modulated by the degree of exposure of the animal to sunlight. Hence, this work aimed to verify whether dietary vitamin D-3 modifies meat quality without negatively affecting animal performance and carcass traits in B. indicus beef cattle that were either exposed to or protected from natural sunlight. Forty-two (411 +/- 38 kg) Nellore-type castrated males were fed a high-concentrate diet for 45 days after assignment to a treatment group. The treatments comprised combinations of three levels of vitamin D3 [ViTD - none (V0) or 2 x 10(6) IU of vitamin D-3 administered for either 2 (V2) or 8 (V8) consecutive days pre-slaughter] and two shading conditions (SHADE - unshaded or shaded). The post-mortem (pm) measurements were taken in the Longissimus thoracis et lumborum muscle. The animal performance and carcass traits were unaffected by ViTD or SHADE The V2 treatment increased the Myofibrillar Fragmentation Index in shaded animals compared to unshaded ones. Animals under shade had higher muscle calcium concentration. There was no effect of either ViTD or SHADE on the shear force. The L* values were higher at 24 h pm than at 0 and 1 h pm, with no differences among the animals in the ViTD or SHADE groups. Higher a* values were observed among animals in the V8 group than in the V0 group, and higher b* values were observed among animals in the V8 group than in the V2 or V0 groups, which were not different. In conclusion, ViTD and SHADE did not affect animal performance, carcass traits or shear force, whereas animals receiving a lower ViTD dosage and SHADE exhibited altered myofibrillar fragmentation. ViTD affected the colour parameters, and changes in the lightness of the beef related to the time pm were found in meat from animals under SHADE. (c) 2012 Elsevier B.V. All rights reserved.

Omega-6 polyunsaturated fatty acids prevent atherosclerosis development in LDLr-KO mice, in spite of displaying a pro-inflammatory profile similar to trans fatty acids

The development of atherosclerosis and the inflammatory response were investigated in LDLr-KO mice on three high-fat diets (40% energy as fat) for 16 weeks: trans (TRANS), saturated (SAFA) or omega-6 polyunsaturated (PUFA) fats. The following parameters were measured: plasma lipids, aortic root total cholesterol (TC), lesion area (Oil Red-O), ABCA1 content and macrophage infiltration (immunohistochemistry), collagen content (Picrosirius-red) and co-localization of ABCA1 and macrophage (confocal microscopy) besides the plasma inflammatory markers (IL-6, TNF-alpha) and the macrophage inflammatory response to lipopolysaccharide from Escherichia coli (LPS). As expected, plasma TC and TG concentrations were lower on the PUFA diet than on TRANS or SAFA diets. Aortic intima macrophage infiltration, ABCA1 content, and lesion area on PUFA group were lower compared to TRANS and SAFA groups. Macrophages and ABCA1 markers did not co-localize in the atherosclerotic plaque, suggesting that different cell types were responsible for the ABCA1 expression in plaques. Compared to PUFA, TRANS and SAFA presented higher collagen content and necrotic cores in atherosclerotic plaques. In the artery wall, TC was lower on PUFA compared to TRANS group; free cholesterol was lower on PUFA compared to TRANS and SAFA; cholesteryl ester concentration did not vary amongst the groups. Plasma TNF-alpha concentration on PUFA and TRANS-fed mice was higher compared to SAFA. No difference was observed in IL-6 concentration amongst groups. Regarding the macrophage inflammatory response to LPS, TRANS and PUFA presented higher culture medium concentrations of IL-6 and TNF-alpha as compared to SAFA. The PUFA group showed the lowest amount of the anti-inflammatory marker IL-10 compared to TRANS and SAFA groups. In conclusion, PUFA intake prevented atherogenesis, even in a pro-inflammatory condition. (c) 2012 Elsevier Ireland Ltd. All rights reserved.

Diet-Sensitive Sources of Reactive Oxygen Species in Liver Mitochondria: Role of Very Long Chain Acyl-CoA Dehydrogenases

High fat diets and accompanying hepatic steatosis are highly prevalent conditions. Previous work has shown that steatosis is accompanied by enhanced generation of reactive oxygen species (ROS), which may mediate further liver damage. Here we investigated mechanisms leading to enhanced ROS generation following high fat diets (HFD). We found that mitochondria from HFD livers present no differences in maximal respiratory rates and coupling, but generate more ROS specifically when fatty acids are used as substrates. Indeed, many acyl-CoA dehydrogenase isoforms were found to be more highly expressed in HFD livers, although only the very long chain acyl-CoA dehydrogenase (VLCAD) was more functionally active. Studies conducted with permeabilized mitochondria and different chain length acyl-CoA derivatives suggest that VLCAD is also a source of ROS production in mitochondria of HFD animals. This production is stimulated by the lack of NAD+. Overall, our studies uncover VLCAD as a novel, diet-sensitive, source of mitochondrial ROS.

Pet food: quality and quality improvement

Today’s pet food industry is growing rapidly, with pet owners demanding high-quality diets for their pets. The primary role of diet is to provide enough nutrients to meet metabolic requirements, while giving the consumer a feeling of well-being. Diet nutrient composition and digestibility are of crucial importance for health and well being of animals. A recent strategy to improve the quality of food is the use of “nutraceuticals” or “Functional foods”. At the moment, probiotics and prebiotics are among the most studied and frequently used functional food compounds in pet foods. The present thesis reported results from three different studies. The first study aimed to develop a simple laboratory method to predict pet foods digestibility. The developed method was based on the two-step multi-enzymatic incubation assay described by Vervaeke et al. (1989), with some modification in order to better represent the digestive physiology of dogs. A trial was then conducted to compare in vivo digestibility of pet-foods and in vitro digestibility using the newly developed method. Correlation coefficients showed a close correlation between digestibility data of total dry matter and crude protein obtained with in vivo and in vitro methods (0.9976 and 0.9957, respectively). Ether extract presented a lower correlation coefficient, although close to 1 (0.9098). Based on the present results, the new method could be considered as an alternative system of evaluation of dog foods digestibility, reducing the need for using experimental animals in digestibility trials. The second parte of the study aimed to isolate from dog faeces a Lactobacillus strain capable of exert a probiotic effect on dog intestinal microflora. A L. animalis strain was isolated from the faeces of 17 adult healthy dogs..The isolated strain was first studied in vitro when it was added to a canine faecal inoculum (at a final concentration of 6 Log CFU/mL) that was incubated in anaerobic serum bottles and syringes which simulated the large intestine of dogs. Samples of fermentation fluid were collected at 0, 4, 8, and 24 hours for analysis (ammonia, SCFA, pH, lactobacilli, enterococci, coliforms, clostridia). Consequently, the L. animalis strain was fed to nine dogs having lactobacilli counts lower than 4.5 Log CFU per g of faeces. The study indicated that the L animalis strain was able to survive gastrointestinal passage and transitorily colonize the dog intestine. Both in vitro and in vivo results showed that the L. animalis strain positively influenced composition and metabolism of the intestinal microflora of dogs. The third trail investigated in vitro the effects of several non-digestible oligosaccharides (NDO) on dog intestinal microflora composition and metabolism. Substrates were fermented using a canine faecal inoculum that was incubated in anaerobic serum bottles and syringes. Substrates were added at the final concentration of 1g/L (inulin, FOS, pectin, lactitol, gluconic acid) or 4g/L (chicory). Samples of fermentation fluid were collected at 0, 6, and 24 hours for analysis (ammonia, SCFA, pH, lactobacilli, enterococci, coliforms). Gas production was measured throughout the 24 h of the study. Among the tested NDO lactitol showed the best prebiotic properties. In fact, it reduced coliforms and increased lactobacilli counts, enhanced microbial fermentation and promoted the production of SCFA while decreasing BCFA. All the substrates that were investigated showed one or more positive effects on dog faecal microflora metabolism or composition. Further studies (in particular in vivo studies with dogs) will be needed to confirm the prebiotic properties of lactitol and evaluate its optimal level of inclusion in the diet.

Strategie nutrizionali finalizzate alla modulazione del microbiota intestinale del cane e del gatto

Il microbiota intestinale riveste un ruolo importantissimo nell’influenzare la salute dell’ospite. È stato dimostrato come la composizione della dieta possa condizionare lo stato di benessere dell’animale, inducendo importanti cambiamenti tra le popolazioni batteriche che coabitano l’intestino; l’uso di prebiotici rappresenta una delle strategie maggiormente impiegate per modulare positivamente la composizione ed il metabolismo dell’ecosistema gastroenterico. Il presente progetto di dottorato si è proposto di indagare gli effetti sul microbiota intestinale del cane e del gatto di diete a diverso tenore proteico e contenenti proteine di diversa digeribilità in presenza o meno di sostanze prebiotiche. Inoltre, sono stati valutati gli effetti della presenza di un estratto di Yucca schidigera e di tannini sulla microflora intestinale del gatto. In ultima istanza, sono state valutate le conseguenze di dosi crescenti di lattosio sul benessere intestinale del cane. I risultati del presente studio hanno rilevato come le sostanze prebiotiche influiscono sulla composizione e sul metabolismo della microflora del cane e del gatto, e come l’impiego di diete ricche di proteine possa avere conseguenze negative sull’ambiente intestinale. Tuttavia, la presenza di oligosaccaridi non sembra contrastare gli effetti negativi che diete ad alto tenore proteico potrebbero avere sull’ecosistema intestinale dell’animale. Nella successiva prova è stato evidenziato come l’inclusione nella dieta di estratti di Yucca e tannini possa contribuire a mitigare l’emanazione di sostanze maleodoranti dalle deiezioni degli animali da compagnia. Nel corso dell’ultima prova, nonostante non siano state osservate differenze tra le popolazioni microbiche intestinali, la somministrazione di dosi crescenti di lattosio ha indotto una certa riduzione delle fermentazioni proteolitiche microbiche. Ulteriori studi sono necessari per stabilire in che misura la dieta e gli alimenti “funzionali” possano influire sul microbiota intestinale del cane e del gatto e come queste informazioni possono essere utilizzate per migliorare miratamente l’alimentazione e lo stato di salute degli animali da compagnia.