J. J. Matte

Starch with High Amylose and Low in Vitro Digestibility Increases Short-Chain Fatty Acid Absorption, Reduces Peak Insulin Secretion, and Modulates Incretin Secretion in Pigs

Diets containing different starch types affect peripheral glucose and insulin responses. However, the role of starch chemistry in kinetics of nutrient absorption and insulin and incretin secretion is poorly understood. Four portal vein-catheterized pigs (35.0 ± 0.2 kg body weight) consumed 4 diets containing 70% purified starch [0-63.2% amylose content and 0.22 (slowly) to 1.06%/min (rapidly) maximum rate of in vitro digestion] for 7-d periods in a 4 × 4 Latin square. On d 7, blood was collected for 12 h postprandial with simultaneous blood flow measurement for determining the net portal appearance (NPA) of nutrients and hormones. The NPA of glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide (GIP) during 0-4 h postprandial were lower (P < 0.05) and those of butyrate and total SCFA were higher (P < 0.05) when pigs consumed the diet containing slowly digestible compared with rapidly digestible starch. The peak NPA of insulin occurred prior to that of glucose when pigs consumed diets containing rapidly digestible starch. The kinetics of insulin secretion had a linear positive relation with kinetics of NPA of glucose (R(2) = 0.50; P < 0.01). In conclusion, starch with high amylose and low in vitro digestibility decreases the kinetics of glucose absorption and insulin and GIP secretion and increases SCFA absorption and glucagon-like peptide-1 secretion. In conclusion, starch with high amylose content and a lower rate and extent of in vitro digestion decreased glucose absorption and insulin secretion and increased SCFA absorption.

Effects of supplements of folic acid, vitamin B12, and rumen-protected methionine on whole body metabolism of methionine and glucose in lactating dairy cows.

The present experiment was undertaken to determine the effects of dietary supplements of rumen-protected methionine and intramuscular injections of folic acid and vitamin B(12), given 3 wk before to 16 wk after calving, on glucose and methionine metabolism of lactating dairy cows. Twenty-four multiparous Holstein cows were assigned to 6 blocks of 4 cows each according to their previous milk production. Within each block, 2 cows were fed a diet estimated to supply methionine as 1.83% metabolizable protein, equivalent to 76% of methionine requirement, whereas the 2 other cows were fed the same diet supplemented daily with 18 g of rumen-protected methionine. Within each diet, the cows were administrated either no vitamin supplement or weekly intramuscular injections of 160 mg of folic acid plus 10 mg of vitamin B(12.) To investigate metabolic changes at 12 wk of lactation, glucose and methionine kinetics were measured by isotope dilution using infusions of 3[U-(13)C]glucose, [(13)C]NaHCO(3) and 3[1-(13)C,(2)H(3)] methionine. Milk and plasma concentrations of folic acid and vitamin B(12) increased with vitamin injections. Supplementary B-vitamins increased milk production from 34.7 to 38.9 +/- 1.0 kg/d and increased milk lactose, protein, and total solids yields. Whole-body glucose flux tended to increase with vitamin supplementation with a similar quantitative magnitude as the milk lactose yield increase. Vitamin supplementation increased methionine utilization for protein synthesis through increased protein turnover when methionine was deficient and through decreased methionine oxidation when rumen-protected methionine was fed. Vitamin supplementation decreased plasma concentrations of homocysteine independently of rumen-protected methionine feeding, although no effect of vitamin supplementation was measured on methionine remethylation, but this could be due to the limitation of the technique used. Therefore, the effects of these B-vitamins on lactation performance were not mainly explained by methionine economy because of a more efficient methylneogenesis but were rather related to increased glucose availability and changes in methionine metabolism.

Importance of sanitary environment for growth performance and plasma nutrient homeostasis during the post-weaning period in piglets

Abstract Deterioration of sanitary conditions in piggeries is known to limit growth performance through inducing a moderate immune response. This article reports the results of an experiment performed to reproduce the consequences of bad sanitary conditions on growth performance and nutrient plasma concentrations of piglets after weaning. We propose to use these experimental conditions as a model for studying the interactions between nutrition and pig health. In this experiment, 20 pairs of littermate piglets were selected and weaned at 28 days of age on the basis of their body weight. Within each pair, piglets were pair-fed and each one was affected to one of the two experimental groups. The first group was housed in a clean environment and was fed an antibiotic supplemented standard diet. The second group was kept in unsanitary rooms, mixed with non-experimental piglets and was fed the same standard diet but without antibiotic supplementation. Compared to pigs kept in the clean environment, piglets kept in the unsanitary environment had significantly lower rate of weight gain and feed efficiency from weaning to 20 d post weaning then from 36 – 45 d post weaning. They also displayed higher plasma concentrations of haptoglobin, copper, vitamin B12 and lysine but lower concentrations of glutathione, pyridoxal-5-phosphate, folic acid, threonine and tryptophan. Our results showed that a reduction of growth performance and a modification of nutrient utilization can be induced by decreasing the sanitary quality of environment where pigs are kept after weaning and after transition to another building. This response could be explained by a moderated activation of body defences.

Dietary Oat β-Glucan Reduces Peak Net Glucose Flux and Insulin Production and Modulates Plasma Incretin in Portal-Vein Catheterized Grower Pigs

Net glucose and SCFA flux and insulin secretion into the portal vein might be associated with the incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Our objectives were to clarify this association and study the impact of 2 doses of dietary oat beta-glucan on the variables. Three 35-kg portal vein-catheterized pigs were fed 3 diets containing 0, 3, or 6% oat beta-glucan concentrate (BG0, BG3, and BG6) for 7 d in a repeated 3 x 3 Latin square. On d 7, blood was sampled for 12 h postprandially. Net glucose flux and apparent hormone production were calculated from plasma portal-arterial differences x flow. Postprandially, pigs fed BG6 had lower (P < 0.05) portal glucose at 15, 30, and 45 min and a lower (P < 0.05) net glucose flux during the first hour. Pigs fed BG6 tended to have lower (P < 0.10) portal C-peptide without lowering insulin, indicating that pigs fed BG6 had lower actual insulin release combined with a higher prehepatic retention of insulin. Pigs fed BG6 had lower (P < 0.05) portal GIP and GLP-1, which in turn were correlated (R(2) = 0.81 and 0.88, respectively; P < 0.01) with portal glucose. Pigs fed BG3 and BG6 had a higher (P < 0.05) net SCFA flux than pigs fed BG0, indicating increased fermentation. In conclusion, dietary supplementation of 6% oat beta-glucan concentrate decreased net glucose flux, increased net SCFA flux, and decreased peak apparent insulin production, changes that were associated with GIP and GLP-1 mediation.

The effect of sanitary status degradation and dietary tryptophan content on growth rate and tryptophan metabolism in weaning pigs

Health degradation modifies Trp metabolism through induction of Trp catabolism. This could limit the amount of Trp available for growth. The aims of the present experiment were to investigate the effects of a low grade inflammation and dietary Trp on growth and Trp metabolism. Eighty weaned pigs were assigned to 4 experimental treatments according to a 2 x 2 factorial arrangement: 2 sanitary statuses x 2 dietary Trp contents. The Trp content was deficient (low-Trp: 2.4 and 1.9 g of Trp/kg of the phase I and phase II diets, respectively) or adequate (high-Trp: 2.9 and 2.4 g of Trp/kg of the phase I and phase II diets, respectively). A low grade inflammatory response was induced by housing pigs in unsanitary environment, whereas control pigs were housed in good sanitary conditions. Pigs were not fed ad libitum to avoid feed refusals. Growth performance was calculated 3, 5, and 7 wk after weaning. Blood was sampled 12, 33, and 47 d after weaning for the determination of plasma concentrations of Trp and related metabolites, kynurenine and pyridoxal-5-phosphate. The interaction between sanitary status and dietary Trp was not statistically significant in all measured criteria. Pigs kept in poor sanitary conditions grew slower (P < 0.001) during the entire experimental period and had greater plasma concentrations of haptoglobin (P < 0.001) than pigs housed in good sanitary conditions. Pigs housed in poor sanitary conditions had also decreased Trp plasma concentrations (P < 0.001), but plasma kynurenine concentrations were not affected. Our results indicated that a moderate inflammatory response was obtained by degrading the sanitary quality of environment. Additionally, poor sanitary conditions modified Trp metabolism, indicating that the amount of Trp available for growth and other metabolic functions might be reduced.

Influence of methionine supply on the response of lactational performance of dairy cows to supplementary folic acid and vitamin B12.

The present experiment was undertaken to determine if the effects of supplementary folic acid on lactational performance were caused by improved methylneogenesis and if the supply in vitamin B(12) could affect this metabolic pathway. In this eventuality, supplementary Met, a major source of preformed methyl groups, should reduce the requirements for these vitamins. Sixty multiparous Holstein cows were assigned to 10 blocks of 6 cows each according to their previous milk production. Within each block, 3 cows were fed a diet estimated to supply Met as 1.83% metabolizable protein and 3 cows were fed the same diet supplemented with 18 g of rumen-protected methionine (RPM) to supply Met as 2.23% of metabolizable protein. Within each level of Met, cows received no vitamin supplement or weekly intramuscular injections of 160 mg of folic acid alone or combined with 10 mg of vitamin B(12) from 3 wk before to 16 wk after calving. There was no treatment effect on dry matter intake during pre- and postcalving periods: 13.4 +/- 0.4 and 21.8 +/- 0.4 kg/d, respectively. Milk production was not affected by RPM supplementation. Folic acid and vitamin B(12) given together tended to increase milk production during the 16 wk of lactation. This effect was more pronounced during the first 4 wk of lactation: 37.5, 37.7, and 40.3 +/- 0.9 kg/d for cows receiving no vitamin supplement, folic acid alone, or folic acid combined with vitamin B(12), respectively. Milk fat yield was not affected by treatments. Lactose, crude protein, and total solid yields were greater, in early lactation, in cows injected with folic acid and vitamin B(12) together but this effect diminished as lactation progressed. Intramuscular injections of folic acid alone or combined with vitamin B(12) tended to decrease plasma concentrations of homocysteine from 5.51 microM with no vitamin supplement to 4.54 and 4.77 +/- 0.37 microM, respectively. Results of the present experiment suggest that the effects of the combined supplement of folic acid and vitamin B(12) on lactational performance of dairy cows were not due to an improvement in methyl groups supply, because RPM supplement, a source of preformed methyl groups, did not alter the cow responsiveness to vitamin supplements.

Effect of dietary n-3 fatty acids (fish oils) on boar reproduction and semen quality

The aim of this study was to evaluate the effects of dietary supplementation with different fish oils (rich in PUFA) vs. hydrogenated animal fat (SFA) on semen production and quality, fatty acid composition, and preservation properties in boars under controlled and commercial conditions. In Exp. 1 (in a research station), 44 boars, allocated to 4 dietary treatments, received daily 2.5 kg of basal diet with a supplement of 1) 62 g of hydrogenated animal fat (AF, n = 12); 2) 60 g of menhaden oil containing 18% docosahexanoic acid (DHA) and 15% eicosapentanoic acid (EPA; MO, n = 11); 3) 60 g of tuna oil containing 33% DHA and 6.5% EPA (TO, n = 11); and 4) 60 g of menhaden oil and 2 mg/kg of biotin (MO+B, n = 10). Biotin is a critical factor in the elongation of PUFA. Semen was collected according to 3 successive phases: phase 1 (twice per week for 4 wk); phase 2 (daily collection for 2 wk); and phase 3 (twice per week for 10 wk). Experiment 2 was conducted in commercial conditions; 222 boars were randomly allocated to AF, MO, and TO treatments. Semen was collected twice weekly over a 6-mo period. All diets were balanced to be iso-energetic and provided an equivalent of 989 mg of vitamin E per day. Classical measurements of sperm quantity and quality were done for both experiments. Experiment 1 showed, after 28 wk of supplementation, a massive transfer of n-3 PUFA into sperm from boars fed fish oil diets (MO and TO). No differences were observed among dietary treatments for libido (P > 0.30), sperm production (P > 0.20), or percentage of motile cell (P > 0.20). Unexpectedly, MO+B diet reduced the percentage of normal sperm compared with the other treatments (P < 0.03). In conclusion, although it modified the fatty acid composition of sperm, supplementation of boars with dietary fish oils, rich in long chain n-3 fatty acids, did not influence semen production or quality postejaculation.

Effects of the forage to concentrate ratio on B-vitamin concentrations in different ruminal fractions of dairy cows

Two studies were undertaken to verify the effect of the forage to concentrate ratio of the diet on B-vitamin concentrations in ruminal contents. In Study 1, eight primiparous and eight multiparous cows were used in a cross-over design, and concentrations of biotin, folates and vitamin B12 were determined in ruminal fluid and plasma of cows fed a high-forage (HF; 58:42 forage to concentrate ratio; DM basis) or a low-forage (LF; 37:63 forage to concentrate ratio; DM basis) diet. In Study 2, six ruminally cannulated lactating cows were used in a cross-over design to evaluate the effects of forage to concentrate ratio (HF = 60:40; LF = 40:60; DM basis) on concentrations of seven B-vitamins in the particle-free fluid and in both liquid- and solid-associated bacteria. Results showed that B-vitamins were present mainly in the bacterial fractions of the ruminal content, while only limited amounts were found in the surrounding fluid. A change in the forage to concentrate ratio had a greater effect on vitamin conce...

Dietary omega-3 fatty acids (fish oils) have limited effects on boar semen stored at 17 °C or cryopreserved

To evaluate the influence of dietary supplementation of omega-3 polyunsaturated fatty acids (n-3 PUFA) on storage of boar semen, three experiments were conducted: two involved long-term, fresh semen storage (Exp. 1 and Exp. 2), whereas the other involved cryopreservation (Exp. 3). Boars were allocated randomly to three dietary treatments (for 6-7 mo). In addition to a daily allowance of 2.5 kg of a basal diet, they received: 1) 62 g of hydrogenated animal fat (AF); 2) 60 g of menhaden oil (MO), containing 18% docosahexanoic acid (DHA) and 15% eicosapentanoic acid (EPA); or 3) 60 g of tuna oil (TO), containing 33% DHA and 6.5% EPA. In Experiment 1 (n = 26) and Experiment 2 (n = 18), semen was cooled and stored in vitro for several days at 17 °C before assessment, whereas in Experiment 3 (n = 18), viability, motility, acrosomal integrity, susceptibility to peroxidation (LPO), and DNA fragmentation were determined in fresh and frozen-thawed sperm. In Experiment 1, sperm from boars fed TO had better resistance to fresh storage; even after 7 or 9 d of storage at 17 °C, there were more (P = 0.03) motile sperm in boars fed TO (>60%) than in those fed AF or MO. In Experiment 2, fish oil supplementation did not influence any aspect of sperm quality during semen storage (P > 0.10). In Experiment 3, cryopreservation decreased the proportion of motile and viable frozen-thawed sperm as well as acrosomal integrity and increased DNA fragmentation and LPO (P < 0.01) relative to fresh semen, although sperm quality was unaffected by treatments (P > 0.09). In conclusion, although adding fish oil to the diet failed to significantly improve the quality of cryopreserved boar sperm, inconsistent responses of long-term storage of cooled sperm to dietary n-3 PUFA supplementation warrant further investigation.

The effect of microbial phytase on true and apparent ileal amino acid digestibilities in growing-finishing pigs,

Ten 56-d-old, 15-kg barrows were surgically fitted with a postvalvular T-cecum cannula at the ileo-cecal junction to evaluate the effect of microbial phytase on apparent and true ileal AA digestibility and N utilization. A semipurified cornstarch- and soybean meal-based diet was formulated to contain 3.4 Mcal of DE/kg, 17.0% CP, 0.8% Ca, and 0.6% P but had a low phytate-P concentration (0.13%; all on an as-fed basis). Chromic oxide and dysprosium chloride were used as indigestible markers. The basal diet was supplemented with 0 or 1,000 phytase units/kg of microbial phytase. Postprandial plasma urea N and alpha-amino N concentrations, excretion of Ca, P, and N in feces and urine, and ileal AA digestibilities were determined 3 times at 4-wk intervals beginning at 70 d of age. The homoarginine (HA) method was used to determine endogenous AA flow by replacing 50% of the basal protein with guanidinated protein. Microbial phytase had no effect on apparent ileal digestibility (AID) or on true ileal digestibilities of N and most AA but did increase AID for arginine (P = 0.006) and methionine (P = 0.037). However, in HA diets, phytase increased the AID of CP (P = 0.01) and several AA. Addition of microbial phytase had no effect on the postprandial alpha-amino N concentrations in plasma but increased overall plasma urea N concentrations (P = 0.035). Barrows fed phytase-supplemented diets had decreased P in feces (P = 0.003) and greater P in urine (P = 0.001) but comparable total P excretion compared with barrows fed no phytase-supplemented diets. In conclusion, the addition of phytase to a semi-purified soybean meal-based diet did not affect the AID of several AA. In addition, differences between the basal and HA diets in N digestibilities indicated that that guanidination may limit the use of the HA method in determining endogenous protein losses.