Obesity leads to changes in the gut microbial community which contribute to the metabolic dysregulation in obesity. Dietary fat and fiber affect the caloric density of foods. The impact of dietary fat content and fiber type on the microbial community in the hind gut is unknown. Effect of dietary fat level and fiber type on hindgut microbiota and volatile fatty acid (VFA) profiles was investigated. Expression of metabolic marker genes in the gut, adipose tissue and liver was determined. A 2×2 experiment was conducted in pigs fed at two dietary fat levels (5% or 17.5% swine grease) and two fiber types (4% inulin, fermentable fructo-oligosaccharide or 4% solka floc, non-fermentable cellulose). High fat diets (HFD) resulted in a higher (P<0.05) total body weight gain, feed efficiency and back fat accumulation than the low fat diet. Feeding of inulin, but not solka floc, attenuated (P<0.05) the HFD-induced higher body weight gain and fat mass accumulation. Inulin feeding tended to lead to higher total VFA production in the cecum and resulted in a higher (P<0.05) expression of acyl coA oxidase (ACO), a marker of peroxisomal β-oxidation. Inulin feeding also resulted in lower expression of sterol regulatory element binding protein 1c (SREBP-1c), a marker of lipid anabolism. Bacteria community structure characterized by DGGE analysis of PCR amplified 16S rRNA gene fragments showed that inulin feeding resulted in greater bacterial population richness than solka floc feeding. Cluster analysis of pairwise Dice similarity comparisons of the DGGE profiles showed grouping by fiber type but not the level of dietary fat. Canonical correspondence analysis (CCA) of PCR- DGGE profiles showed that inulin feeding negatively correlated with back fat thickness. This study suggests a strong interplay between dietary fat level and fiber type in determining susceptibility to obesity.

The β-adrenergic agonist ractopamine is increasingly used in the swine industry due to higher consumer demand for leaner pork products. Redirecting nutrients to favor leanness rather than fat deposition, ractopamine improves growth and carcass traits of finishing pigs. However, the impact of this agonist on pork quality is not clearly defined. Understanding the biological effects of dietary ractopamine dose, treatment period, lysine levels, and the lysine to metabolizable energy ratio will help pork producers achieve improvements in animal performance, carcass leanness, and economic efficiency in swine production systems.

BackgroundThere has been an increased interest in nutritional strategies to manipulate the fatty acid pro le of pigs. Dietary regimens involving the use of oils that are high in monosaturated fatty acid (MUFA), primarily oleic acid (OA), such as canola oil (CO), as well as in omega (n)-3 polyunsaturated fatty acid (PUFA), which are found in sh oil (FO), have been investigated aiming healthier fatty acid pro le cuts, with a higher ratio of n-3 to n-6 fatty acids. Therefore, the effects of including 3% soybean oil (SO), CO, or FO in growing-nishing pig diets vs. feeding a standard commercial diet with 1.5% SO (control) on growth performance, carcass traits, meat quality, consumer acceptability, and intramuscular fatty acid composition of the longissimus lumborum (LL) muscle were evaluated. ResultsDietary treatments had no effect on overall growth performance and pig carcasses. Although loins from pigs fed diets containing either 3% SO or CO showed a reduction (P = 0.05) in Warner-Bratzler shear force, only the addition of 3% SO to pig diets resulted in loin chops that were rated higher (P < 0.001) for consumer overall liking. Adding either 3% SO or CO increased (P < 0.01) the percentages of OA and total MUFA in the LL intramuscular fat compared to controlor FO-fed pigs. However, intramuscular fat from 3% SO-or CO-fed pigs had the lowest (P < 0.01) proportion of total n-3 PUFA than control-or FO-fed pigs.Including 3% fat, regardless of source, reduced (P < 0.01) total PUFA, total n-6 PUFA, and PUFA:saturated fatty acid (SFA) ratio than control-fed pigs. Dietary FO inclusion decreased (P < 0.01) n-6:n-3 PUFA ratio, but also increased total SFA (P < 0.01) and atherogenic index (P = 0.02) in the LL intramuscular fat. ConclusionsAlthough adding 3% CO or FO to pig diets provided slight nutritional bene ts to consumers in terms of MUFA and long chain n-3 PUFA contents, respectively, formulating growing-nishing diets with 1.5% SO was adequate enough in terms of LL intramuscular fatty acids composition for high quality meat destined to human consumption. BackgroundNutritional interventions play a major role in e ciently producing lean, quality pork for processing and storage, including retail display. Apart from being recognized as excellent energy sources, fats comprise a practical dietary strategy for improving pig productivity [1]. Fat-rich diets have been implemented for growing-nishing pigs to decrease voluntary feed intake and improve feed e ciency [2, 3], as well as to alleviate the energy loss as heat increment, especially in heat stress conditions [4]. Additionally, fats are sources of fat-soluble vitamins, essential fatty acids, and may act as signaling molecules [5]. However, feeding supplemental fat to pigs may be limited by the cost effectiveness in least-cost formulation [6].Collectively, all animal products provide 56% of the total fat, 74% of the saturated fatty acids (SFA), 70% of the protein, and 100% of the cholesterol consumed [7]. Dietary guidelines for humans in the last years have focused on limiting ...

Com este trabalho objetivou-se avaliar os efeitos de níveis de nucleotídeos em dietas para leitões recém-desmamados sobre o desempenho, a morfometria de órgãos e a histologia do epitélio intestinal. Foram utilizados 144 leitões desmamados aos 21 dias de idade e com peso médio inicial de 5,80 ± 0,16 kg em um experimento inteiramente ao acaso, com seis dietas, seis repetições por dieta e quatro animais por baia (unidade experimental). As dietas foram: Am (antimicrobiano) _ dieta basal com inclusão de 40 ppm de sulfato de colistina, assim como dieta basal contendo 0, 150, 300, 450 e 600 ppm de nucleotídeos. Ao final do experimento, foi abatido um animal de cada baia para coleta das amostras e avaliação da morfometria de órgãos e da histologia do epitélio intestinal. No período de 1 a 14 dias de experimentação, houve piora linear das características de desempenho e, no período total de 34 dias, redução linear do peso final dos animais com o aumento dos níveis de nucleotídeos na dieta. Os leitões alimentados com a dieta contendo colistina apresentaram maior comprimento do intestino delgado e menor relação altura de vilosidade:profundidade de cripta (AV:PC) no duodeno em comparação àqueles que receberam nucleotídeos. Foram observados, também, aumento linear no peso relativo do baço e na relação AV:PC e redução linear da profundidade de cripta no duodeno dos animais com a adição de nucleotídeos na dieta. Assim, embora não tenha promovido melhora no desempenho, a adição de até 600 ppm de nucleotídeos em dietas complexas melhora a morfometria de órgãos e a histologia do epitélio intestinal de leitões recém-desmamados.