Fernando Bas

The domestic pig (Sus scrofa domestica) as a model for evaluating nutritional and metabolic consequences of bariatric surgery practiced on morbid obese humans

M. Gandarillas, and F. Bas. 2009. The domestic pig (Sus scrofa domestica) as a model for evaluating nutritional and metabolic consequences of bariatric surgery practiced on morbid obese humans. Cien. Inv. Agr. 36(2):163-176. The prevalence of obesity has increased dramatically over the last 20 years. Moreover, morbid obese patients routinely suffer from serious medical problems, especially cardiovascular disease. Medical therapy for morbid obesity offers no substantial long-term benefi t, and thus the fi rst choice therapy for severe obesity is effectively surgery. Gastrointestinal surgery for obesity, also called bariatric surgery, alters the digestive process by limiting food intake and facilitating malabsorption of nutrients from the diet. This article reviews the types and evolution of morbid obesity surgery performed in humans and proposes the pig model as an alternative when practicing new surgical techniques or improving actual procedures, as well as to evaluate the metabolic consequences of these procedures. Based on similarities between humans and pigs in terms of their anatomical, physiological and metabolic characteristics, the pig also provides an opportunity to develop, evaluate specifi c techniques in open and laparoscopic surgery. Finally, a complete review of macronutrient digestion and absorption between pigs and humans is done in order to justify the use of this model. Therefore, the objective of this article was to illustrate the use of the pig as a model for studying nutrient digestion and absorption in humans who undergo bariatric surgery and to review how, through digestibility trials, a digestion and absorption assessment of nutrients should complement classical human assessments with surgery.

Endocrine changes during pregnancy, parturition and post-partum in guanacos (Lama guanicoe)

Plasma concentrations of progesterone (P4), estradiol-17beta (E2), estrone (E1) and estrone sulfate (E1S) were measured during gestation in eight guanacos kept in captivity. Gestational length was 346.1+/-9.8 days. P4 plasma concentrations increased after ovulation and remained elevated until parturition. However, during the last 4 weeks of gestation, a gradual decrease from 4.17x1.17(+/-1)nmol/L to 2.02x1.95(+/-1)nmol/L on day 5 before parturition was observed, followed by a more abrupt final decline to baseline concentrations which were reached on the day after parturition. Mean E2 plasma concentrations started to increase during the eighth month of gestation, and were significantly elevated up to maximum concentrations of 484.7x1.21(+/-1)pmol/L during the last 2 months of pregnancy. Concentrations returned to baseline during the last 2 days of gestation. An increase of E1S concentrations (p<0.01) was observed in the eleventh month of gestation. Mean E1S concentrations remained rather constant during the last 3 weeks of gestation between 4 to 8nmol/L until parturition, when a steep precipitous decline was observed. E1 concentrations were slightly elevated during the last 4 weeks of gestation, however, maximum concentrations did not exceed 1.5nmol/L. The results show distinct species specific features of gestational steroid hormone profiles in the guanaco in comparison to domestic South American camelids, such as a more pronounced gradual prepartal decrease of P4 concentrations prior to the final decline to baseline, and clearly lesser E1S concentrations during the last 4 weeks of gestation, which lack a continuous prepartal increase.

Effect of three different bariatric obesity surgery procedures on nutrient and energy digestibility using a swine experimental model.

Morbid obesity is a worldwide health concern that compromises life quality and health status of obese human subjects. Bariatric surgery for treating morbid obesity remains as one of the best alternatives to promote excess weight loss and to reduce co-morbidities. We have not found studies reporting nutrients and energy balance considering digestibility trials in humans following surgery. The purpose of this study was to determine protein, lipid, fiber, energy, calcium, and phosphorous digestibility in a swine model that underwent ileal transposition (IT), sleeve gastrectomy with ileal transposition (SGIT), Roux-en-Y gastric bypass (RYGBP), and with sham operated animals (SHAM). Thirty-two pigs were randomly assigned to four laparoscopic procedures: IT (n = 8), RYGBP (n = 8), SGIT (n = 8), and Sham-operated pigs (n = 8). From day 0 postsurgery to 130, pigs were weighed monthly to determine live weight and weight gain was calculated for each month postsurgery until day 130. Food intake in a metabolic weight basis was calculated by measuring ad libitum food intake at day 130. Swine were fitted into metabolic crates to determine digestibility coefficients of dry matter, protein, fat, fiber, ash, energy, calcium, and phosphorous from day 130. A one-way ANOVA and Student–Newman–Keuls were used to detect differences in weight, food intake, and digestibility coefficients. Digestibility values for dry matter, fiber, phosphorus, and energy showed no differences among groups (P > 0.05). However, significant differences (P ≤ 0.05) were encountered among groups for fat, protein, ash, and calcium digestibilities. The RYGBP procedure, when applied to the pig model, significantly reduced calcium, fat, and ash digestibility, which did not occur with SGIT or IT procedure, when compared with Sham-operated animals.

Nutrient absorption, feed intake and liveweight change as a consequence of Roux-en-Y gastric bypass with increasing alimentary limb lengths in the pig model

Roux-en Y gastric bypass (RYGBP) combines a restrictive and malabsortive component of the digestive system. Metabolic outcomes of increasing the latter, is a matter of research interest. The aim of this study was to evaluate the nutritional consequences of RYGBP with different alimentary limb lengths using a pig model. Twenty-six pigs were randomly assigned to four laparoscopic procedures: RYGBP with 300 cm of alimentary limb (T300); RYGBP with 600 cm (T600); RYGBP with 900 cm (T900); sham operation (TS). RYGBP consisted of creating a proximal gastric pouch with a 300, 600 and 900 cm alimentary limb. Sham operation was performed by bowel transections and reanastomosis in the ileum and proximal jejunum together with gastrotomy and closure. Animals were evaluated weekly for weight increase and monthly for food intake. Eighteen weeks after surgery, fecal in vivo apparent digestibility of protein, fat, fiber, calcium and phosphorous were determined. We performed ANOVA and Tukey tests to detect differences in weight, feed intake and digestibility. We observed significant differences in liveweight after 10 weeks among T300, T600 and T900 as compared to TS. No differences were found among T300, T600 and T900. We also observed significant differences in feed intake among T300, T600 and T900 versus TS. No differences among treatments for digestibility of fat; fiber; protein and energy were found. Calcium and phosphorous apparent digestibility differed among treatments. RYGBP reduced weight increase in the porcine model and calcium and phosphorous digestibility was reduced with longer limbs.