José Adalberto Fernández

Prediction of the total tract digestibility of energy in feedstuffs and pig diets by in vitro analyses

Abstract An in vitro method consisting of a three-step enzymatic incubation for the prediction of total tract energy digestibility is described. The effects of all relevant parameters in the incubation conditions on the in vitro digestibility were investigated carefully in order to obtain a method with a general validity for all common feedstuffs used in pig diets. A close linear relationship between the in vitro enzyme digestibility of organic matter (EDOM) and in vivo total tract digestibility of energy (dE) was demonstrated for 90 samples of 31 different feedstuffs: dE, % = − 14.0(±2.1) + 1.106(±0.026) × EDOM, % ( n = 90, r 2 = 0.94, RSD = 3.4, CV = 4.4). Five samples of meat and bone meal and raw potato starch were overestimated or underestimated, respectively, by the in vitro method. These two feedstuffs were therefore not included in the equation. On the other hand, the equation was also valid for experimental pig diets which were formulated with a considerable variation in feedstuff composition and also including diets with these two feedstuffs. A close relationship between determined dE and predicted dE for these feed mixtures by the use of the above equation was found ( n = 34, r 2 = 0.87, RSD = 2.3, CV = 2.9). Thus, the described in vitro approach for energy evaluation appears to have a significant potential for practical purposes.

Chemical Composition and Energy Value of Different Fat Sources for Growing Pigs

The chemical composition, digestibility and energy value of eight animal and vegetable fat batches was determined (animal fat, soya oil, palm oil, palm oil, palm oil mix and vegetable oil byproduct). To a basal diet, 5, 10, 15, 20, 25 or 30% dietary fat was added, and digestibility and balance experiments with each fat batch were carried out with three litters of six female pigs, weighing 50-75 kg. The digestibility was determined by multiple regression analysis. The content of HCl-extracted fat and the amount of gross energy was nearly equal for all the fat sources and as such not related to the variation in fatty acid composition or digestibility. Inclusion of soya oil, which is high in polyunsaturated fatty acids, enhanced protein digestibility, whereas inclusion of the other fat sources did not influence protein digestibility. A curvilinear function of fat digestibility (% of intake) to dietary fat concentration was found, thus reflecting the significance of the endogenous fat losses on the determined digestibility value. In contrast, the relationship of digested fat (g day

Absorption and metabolism of benzoic acid in growing pigs.

Dietary benzoic acid (BA) supplementation causes a pronounced reduction in urinary pH but only small changes in blood pH. The present study aimed to investigate the portal absorption profile, hepatic metabolism of BA, and renal excretion of hippuric acid (HA) underlying the relatively small impact of BA on systemic acid-base status. Eight growing pigs (BW = 63 +/- 1 kg at sampling) fitted with permanent indwelling catheters in the abdominal aorta, hepatic portal vein, hepatic vein, and mesenteric vein were allocated to 4 sampling blocks and randomly assigned to control (CON; nonsupplemented diet) or BA supplementation (B; control diet + 1% BA top-dressed). Feed intake was restricted to 3.6% of BW and the ration divided into 3 equally sized meals offered at 8-h intervals. Blood pH (7.465 and 7.486 +/- 0.004) and urinary pH (4.99 and 7.01 +/- 0.09) were less (P = 0.03 and P < 0.01) in B compared with CON. The arterial concentration, net portal flux, and net hepatic uptake of BA increased (P < 0.01) in B compared with CON. The net portal flux of BA increased (P < 0.01) after feeding with B, but remained positive (P < 0.01) at all sampling times (n = 8). Recovery of dietary BA as increased net portal flux and hepatic uptake of BA was 87 +/- 5% and 89 +/- 15%, respectively. The recovery of dietary BA as urinary excretion of BA and HA was 0.08 +/- 0.02% and 85 +/- 7%, respectively. It is concluded that the small impact of BA supplementation on systemic acid-base status was caused by a protracted BA absorption and efficient hepatic extraction and glycine conjugation in combination with efficient renal clearance of HA. Together, these physiological mechanisms prevented major BA and HA accumulation in body fluids.

Influence of nitrogen fertilization on the nutritional value of high-lysine barley determined in growing pigs

An experiment was performed to examine the nutritional value of a high-lysine barley variety, Ca 7200202 (HLys) and four conventional barley varieties, namely cultivated varieties (cv) Galant, Inga, Romi and Zita, which were fertilized with either 0 or 180 kg nitrogen (N) ha ˇ1 . The barley varieties were used in N balance and digestibility studies in growing pigs. The lysine content of protein in cv HLys was 4.93 g/16 g N, at least 35.1% higher (p < 0.05) than the level of lysine in protein in the conventional varieties which ranged from 3.38 to 3.65 g/16 g N. In contrast, cv HLys had the lowest (p < 0.05) levels of glutamic acid and proline, 14.71 and 6.24 g/16 g N, respectively, which were at least 32.8% and 38.6%, respectively, lower than in the other barley varieties. N fertilization increased (p < 0.05) the protein (N 6.25) level in the barley varieties from 95.0 to 147.0 g/kg dry matter (DM). The content (g/kg DM) of lysine, threonine and methionine in barley grain increased (p < 0.05) by 31.6%, 40.1% and 41.8%, respectively. Pigs fed the fertilized barley varieties retained more (p < 0.05) N and had a higher (p < 0.05) growth rate than pigs fed the unfertilized barley varieties. Pigs fed cv HLys retained the most (p < 0.05) N and cv HLys had the highest (p < 0.05) apparent biological value (BV, N retained/N digested). It is concluded that the development of high-lysine barley varieties is very beneficial for meeting the requirements of indispensable amino acids in pigs, and N excretion into the environment is substantially reduced due to a reduction in the prolamin (hordein) fraction which is rich in glutamic acid and proline. Furthermore, N fertilization greatly increases the nutritive value of barley by increasing the level of protein and therefore the concentration of indispensable amino acids. # 1999 Elsevier Science B.V. All rights reserved.

Effects of quinoa hull meal on piglet performance and intestinal epithelial physiology

Saponin-containing feed additives have shown positive effects on pig performance. Quinoa hull has high saponin content and may be of interest as a feed additive. This study aimed to evaluate quinoa hull meal (QHM) as a feed additive in a pig diet. The effects of QHM were assessed for three dosages of South American (SA) origin (100, 300 and 500 mg/kg) and one dosage of Danish (DK) quinoa (300 mg/kg). In addition, the effect of dietary SA-QHM and SA-QHM-extract on jejunal epithelial physiology was studied ex vivo in Ussing chambers. The experiment included 400 piglets weaned at 28 ± 2 days of age and the experimental period was 4 weeks. Piglets were weighed initially and finally and feed intake registered. The ex vivo studies were performed with epithelium from 40 pigs receiving control or SA-QHM. Epithelium from each pig was placed into eight Ussing chambers, where four concentrations of SA-QHM-extract were added. Epithelial permeability, Na(+)-dependent glucose transport and serotonin (5-HT) and theophylline-induced secretion were measured. The results showed that QHM had no influence on piglets growth (p = 0.41) or feed intake (p = 0.17). In spite of a large difference in saponin content between SA-QHM and DK-QHM (28.7% and 2.0% w/w respectively) the source did not affect pig performance. The ex vivo studies revealed no effect (p > 0.05) of adding QHM-extract into the medium. The permeability and glucose induced absorption were highest (p = 0.003 and p = 0.04 respectively) in epithelium from pigs that consumed 100 or 300 mg/kg SA-QHM. The secretory response to 5-HT was not affected (p = 0.59) by dietary treatments, but the theophylline-induced secretion decreased (p = 0.02) with increasing dietary SA-QHM. The changes in epithelial physiology measured ex vivo did not affect animal performance in vivo in this study.

Ileal digestibility of sunflower meal, pea, rapeseed cake, and lupine in pigs

The standardized ileal digestibility (SID) of CP and AA was evaluated in soybean (Glycine max) meal, sunflower (Helianthus annuus) meal, rapeseed cake, and field pea (Pisum sativum) using 10 pigs and in lupine (Lupinus angustifolius) using 7 pigs. Pigs were fitted with either a T-cannula or a steered ileocecal valve-cannula. Diets contained 170 to 186 g CP/kg DM. Endogenous losses of CP and AA were estimated by feeding a N-free diet. The SID was calculated using the average of Cr(2)O(3) and TiO(2) as indigestible markers and corrected for type of cannula. The SID of CP was greater (P < 0.05) for soybean meal and pea compared to sunflower meal, rapeseed cake, and lupine. The SID of Lys and His were lowest (P < 0.05) in sunflower meal, and the SID of Met and Val were lowest (P < 0.05) in lupine. These results imply soybean meal and pea to be a high-digestible protein source relative to sunflower meal, rapeseed cake, and especially lupine, although all tested feedstuffs seem appropriate for inclusion in diets for organic pigs.