Influence of dietary fiber on luminal environment and morphology in the small and large intestine of sows

In this study, the effect of feeding different types and amounts of dietary fiber (DF) on luminal environment and morphology in the small and large intestine of sows was studied. Three diets, a low-fiber diet (LF) and 2 high-fiber diets (high fiber 1, HF1, and high fiber 2, HF2) were used. Diet LF (DF, 17%; soluble DF 4.6%) was based on wheat and barley, whereas the 2 high-fiber diets (HF1: DF, 43%; soluble DF, 11.0%; and HF2: DF, 45%; soluble DF, 7.6%) were based on wheat and barley supplemented with different coproducts from the vegetable food and agroindustry (HF1 and HF2: sugar beet pulp, potato pulp, and pectin residue; HF2: brewers spent grain, seed residue, and pea hull). The diets were fed for a 4-wk period to 12 sows (4 receiving each diet). Thereafter, the sows were killed 4 h postfeeding, and digesta and tissue samples were collected from various parts of the small and large intestine. The carbohydrates in the LF diet were well digested in the small intestine, resulting in less digesta in all segments of the intestinal tract. The fermentation of nonstarch polysaccharides in the large intestine was affected by the chemical composition and physicochemical properties. The digesta from pigs fed the LF diet provided low levels of fermentable carbohydrates that were depleted in proximal colon, whereas for pigs fed the 2 high-DF diets, the digesta was depleted of fermentable carbohydrates at more distal locations of the colon. The consequence was an increased retention time, greater DM percentage, decreased amount of material, and a decreased tissue weight after feeding the LF diet compared with the HF diets. The concentration of short-chain fatty acids was consistent with the fermentability of carbohydrates in the large intestine, but there was no effect of the dietary composition on the molar short-chain fatty acid proportions. It was further shown that feeding the diet providing the greatest amount of fermentable carbohydrates (diet HF1, which was high in soluble DF) resulted in significant morphological changes in the colon compared with the LF diet.     

Feeding high fibre diets changes luminal environment and morphology in the intestine of sows

Sows were fed three diets varying in type and level of dietary fibre (DF). The low fibre diet (LF; 17% DF) was based on wheat and barley. In the two high DF diets (HF1, high in soluble DF and HF2, high in insoluble DF;  44% DF), the cereal part of the diet was substituted with different co-products (sugar beet pulp, potato pulp, pectin residue, pea hull, brewer's spent grain, and seed residue). The diets were fed for a four-week period to 12 sows (4 for each diet). Sows were stunned 4 h post-feeding, and digesta and tissue samples were collected from various parts of the small and large intestines. The carbohydrate load to the large intestine was 538–539 g/d when feeding the high DF diets and 190 g/d when feeding diet LF. Feeding sows the high DF diet containing large proportion of soluble DF resulted in a lower dry matter content of digesta (23 contra 28%), a higher tissue weight (2.9 contra 2.0 kg), and a higher crypt depth (492 contra 330 μm) and area (23,201 contra 15,751 μm²) in the colon compared with the low DF diet. In conclusion, increasing the amount of DF in the diet for sows resulted in an increased amount of digesta entering the large intestine which influences the functional properties of digesta. Furthermore, a high DF diet with a high proportion of soluble DF increases tissue weight, crypt depth and crypt area in the midcolon compared to a low fibre diet.     

Feeding motivation and plasma metabolites in pregnant sows fed diets rich in dietary fiber either once or twice daily

The present study investigated the effects of source and level of dietary fiber (DF) and feeding frequency (once vs. twice daily) on feeding motivation and plasma metabolites at 4 different time points post feeding. Sixty pregnant sows (Sus scrofa, 4 blocks of 15 sows) were allocated to 1 of 5 diets within blocks. Four diets were restricted (approximately 35 MJ ME/d): a barley and wheat control diet (171 g DF/kg DM; 12 g DF/MJ ME), and 3 fiber diets formulated to contain 35% DF by including pectin residue (323 g DF/kg DM; 25 g DF/MJ ME), potato pulp (404 g DF/kg DM; 29 g DF/MJ ME), or sugar beet pulp (367 g DF/kg DM; 25 g DF/MJ ME). The fifth diet was a mixture including an equal amount of the 3 fiber diets offered semi ad libitum (ad libitum access to feed during 6 periods of 1 h starting at 0300, 0600, 1100, 1500, 1800, and 2300; 354 g DF/kg DM; 25 g DF/MJ ME). The experimental period included 2 periods of 4 wk each. Restricted-fed sows were fed once daily (0800 h) during the first period and twice daily (0800 and 1500 h) during the second period, or vice versa. Semi ad libitum fed sows had access to feed 6 times a day in both periods. In each period, the feeding motivation was assessed in an operant conditioning test, and samples of peripheral blood were taken in a balanced design, at 0900, 1200, 1900, and 0700 h, corresponding to 1, 4, 11, and 23 h after feeding for restricted sows fed once daily. No differences in the feeding motivation were found between the 4 restricted diets at any of the time points post feeding, but semi ad libitum fed sows had a decreased feeding motivation (P < 0.001). Among the restricted-fed sows, feeding twice daily resulted in decreased feeding motivation at 1900 h (P < 0.001) and at 0700h (P < 0.05) compared with feeding once daily, but not at 0900 and 1200 h, indicating that feeding twice daily reduced feeding motivation during the night compared with feeding once daily. Among restricted-fed sows, plasma concentrations of short-chain fatty acids (SCFA) were greater in sows fed high-fiber diets compared with the control (P = 0.02). Nonesterified fatty acid was least in sows on the control diet and greatest in sows on the potato diet, whereas sows on the pectin and sugar beet diets were intermediate (P < 0.001). Less diurnal variation in glucose (P < 0.001) was seen in sows on high-fiber diets. In spite of the found effects on plasma metabolites, the applied level of fiber in the diet of restrictedly fed sows did not reduce their feeding motivation irrespective of fiber source.     

The absorption of lactic acid is more synchronized with the absorption of glucose than with the absorption of short-chain fatty acids — A study with sows fed diets varying in dietary fibre

Sows were fed one of three diets varying in level and type of dietary fibre (DF). A low DF diet (LF; 17% DF) based on wheat and barley and two generic high DF diets (HF1, high in soluble DF and HF2, high in insoluble DF;  41% DF) where the cereals were substituted with co-products (sugar beet pulp, potato pulp, pectin residue, pea hull, brewer's spent grain and seed residue (ray grass)) from the vegetable food and agro industries. Six sows were fitted with a catheter in the portal vein and the mesenteric artery and a flow probe around the portal vein. The sows were fed 2 kg/d of the three experimental diets in a repeated 3 × 3 crossover design. Blood samples were collected the last day in each period at − 120, − 60, 0, 15, 30, 45, 60, 90, 120 and then at 60-min intervals up to 600 min after feeding. Although lactic acid (LA) is formed by microbial fermentation, the absorption profile of LA was more comparable with the absorption profile of glucose than with that of other SCFA.     

Evaluation of a dynamic in vitro model to simulate the porcine ileal digestion of diets differing in carbohydrate composition

The aim of the study was to assess the ability of a dynamic in vitro model to determine the digestibility of OM, CP, and starch compared with a validated, static, in vitro method and in vivo ileal digestibility obtained from growing pigs fitted with a T-cannula. Five experimental diets with different carbohydrate types and level were assessed: a standard corn-based diet (ST) or the same diet with coarse ground corn (CC), 8% sugar beet pulp (BP), 10% wheat bran (WB), or 8% sugar beet pulp and 10% wheat bran (HF). In the in vivo experiment, diets CC and HF reduced (P = 0.015) ileal digestibility of OM compared with the ST diet. The inclusion of sugar beet pulp reduced (P = 0.049) ileal CP digestibility of the BP diet. This reduction was not statistically significant when sugar beet pulp was combined with the wheat bran in the HF diet. No differences were shown for in vivo starch digestibility among diets. With the static in vitro method, the OM disappearance was greater than that observed in the in vivo experiment. In this static method, the BP and HF diets reduced (P = 0.004 and < 0.001, respectively) the disappearance of the OM compared with the ST diet. The coarse grinding of corn did not alter OM digestibility but decreased (P = 0.005) the starch digestibility. The R(2) between the in vivo results and the static in vitro methods for OM and starch digestibility was 0.99 when the CC diet was not considered. The dynamic in vitro model yielded OM and CP digestibility coefficients comparable with those obtained in vivo for the ST and CC diets. However, the values were considerably affected by the incorporation of the fibrous ingredients. Diets BP, WB, and HF had decreased (P = 0.009, 0.058, and 0.004, respectively) OM digestibility compared with the ST diet. Protein digestibility was also decreased (P < 0.001, P = 0.019, and P = 0.003, respectively) with the BP, WB, and HF diets compared with the ST diet. However, digestibility was decreased to a greater extent in the BP diet than in the WB and HF diets, both of which contained wheat bran. The R(2) between the dynamic in vitro model and the in vivo results for CP digestibility was 0.99 when the CC diet was not considered. No differences were detected for starch digestibility among the diets with the dynamic in vitro model. This dynamic in vitro model yielded ileal digestibility results comparable with those obtained in vivo for CP and OM with a corn-soybean diet, or with a diet including coarse corn, but it underestimated digestibility when fibrous ingredients were included in the diet.     

Effect of dietary fibre on reproductive performance of sows during the first two parities

The aim of this study was to investigate the effect of dietary fibre on reproductive performance during the first two parities. Gilts were randomly allocated to receive three fibrous diets from days 1-90 of gestation, including low fibre [low fiber (LF), 10.8% neutral detergent fiber (NDF), n=132], middle fibre [middle fiber (MF), 15.8% NDF, n=132] and high fibre diet (HF, 20.8% NDF, n=135), until completion of the second parity. Response criteria included backfat measurements, litter size and pig weight at parturition and day 22 of lactation, weaning-oestrus-interval, oestrus rate, sow farrowing and culling rate, uniformity of newborns and relative organ weights. The results showed sows fed LF diet in parity 1 gained more backfat (p<0.05) during gestation but lost more (p<0.05) during lactation than sows fed HF diet. Furthermore, sows fed LF diet farrowed more pigs (+0.7-1.1 pigs, p<0.05) and pigs born alive (+1.0 pigs, p<0.05) relative to sows fed HF diet. Likewise, sows fed LF and MF diets had greater litter weights at parturition (both p=0.06) and day 22 after lactation (both p<0.05). In parity 2, yet, it was MF diet to increase both total pigs born and pigs born alive (+0.9-1.1 pigs, p<0.05) and litter weight (p=0.05) relative to other diets. After 22 d of lactation, intriguingly, sows fed HF diet had most pigs alive (p<0.01-0.07) and heavier litter weight (p=0.07 or 0.2). Feeding HF diet also increased internal organs weight of newborns (p<0.05). Collectively, feeding LF and MF diets had beneficial effects on litter weight at parturition and day 22 of lactation in parity 1, and feeding MF diet until parity 2 was able to improve litter size and weight at parturition, but this positive effect disappeared after 22 days of lactation, instead feeding HF diet showed the optimal litter performance.     

Effect of live yeast culture supplementation on apparent digestibility and rate of passage in horses fed a high-fiber or high-starch diet

Eight crossbred male horses aged 12 +/- 5 yr and with BW of 305 +/- 18 kg were used in pairs in a 4 x 4 Latin square design with 4 ground and pelleted diets. Each pair included a cecum and right ventral colon-fistulated animal and a cecal-fistulated animal. The 4 horse diets were a high-fiber diet (HF+0) based on dehydrated alfalfa, a high-starch diet based on barley and wheat bran (HS+0), and the HF or HS diets supplemented with Saccharomyces cerevisiae (SC) CBS 493.94 (HF+SC and HS+SC). The probiotic preparation contained 4.5 x 10(9) cfu/g of live yeast mixed with the culture medium, and was top-dressed onto the feed pellets at a rate of 10 g/d, equally distributed between the 2 daily meals. All 4 diets were offered in the same quantities (18.0 g of pelleted feed DM + 3.5 g of long wheat straw/kg of BW per d). Each of the 4 experimental treatments was divided into a 21-d period of diet adaptation followed by a 10-d period of total fecal collection for digesta flow rate and apparent digestibility measurements. Three markers were used to measure mean retention time (MRT) of the feed particles: Yb bound to the pelleted feeds for MRT in the whole digestive tract (MRT(Yb)), Eu bound to the pelleted feeds, and Dy bound to the fecal particles for MRT in the hindgut (MRT(Eu) and MRT(Dy)). Apparent digestibilities of DM, OM, and CP were greater (P < 0.001) in the HS than HF diet, independently of SC supplementation, whereas ADF digestibility was greatest in the HF diet (P = 0.035). Cellulolytic activity estimated through the in vitro disappearance rate of the dietary ADF fraction (IVAD(ADF)) was less (P < 0.001) in the HS than the HF diet. There was no dietary effect on NDF digestibility due to the longer MRT(Eu) of small particles in the hindgut (P = 0.036), which compensated for the lower fibrolytic activity expressed per unit of time in the HS compared with the HF diet. Supplementation with SC improved ADF digestibility (P = 0.038) and stimulated DM (P = 0.030) and NDF (P = 0.038) intakes, but had no effect on the MRT of solid digesta. The absence of any significant diet x SC interaction supports the strategy of using SC to stimulate cellulose digestion and improve the nutritional status of horses under both HF and HS diets.     

Effect of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the gastrointestinal tract of growing pigs

The main objective of the present investigation was to study the impact of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the small intestine and total tract of growing pigs. Eight pigs (initial BW, 34.5 ± 0.9 kg) were used in a replicated 4 × 4 Latin square design. Pigs were cannulated and housed individually in metabolism pens during sample collection. The 4 cereal-based diets were nonfermented liquid barley (NFLB), nonfermented liquid wheat (NFLW), fermented liquid barley (FLB), and fermented liquid wheat (FLW). The fermented feeds were prepared by storing the dietary cereals (barley and wheat) and water [1:2.75 (wt/wt)] in a closed tank at 25 °C for 2 d, after which 50% of the volume was removed and replaced with an equal amount of fresh cereals and water after each afternoon meal. At the time of feeding (0730 and 1430 h), the remaining dietary ingredients were added. Water was added to the dry nonfermented feeds [1:1 (wt/wt)] immediately before feeding. The fermentation process reduced the amount of DM in both cereals (P<0.001), whereas the amount of DM was similar (P=0.626) between the fermented cereals. There was an interaction of cereal and treatment for ileal flow of DM (P=0.014), OM (P=0.013), and protein (P=0.006), which were less in pigs fed the NFLB than the FLB diets, but unchanged in pigs fed the NFLW and FLW diets. Conversely, the ileal flow of protein was similar (P=0.605) in pigs fed the barley diets (average, 47.5 ± 1.7 g/kg of DMI) and increased with the FLW diet compared with the NFLW diet (43 vs. 35 g/kg of DMI, respectively). Ileal fat and CH(2)O digestibilities were 7.6 (P=0.002) and 8.9% (P<0.001) greater, respectively, when pigs were fed wheat compared with the barley-based diets, and the ileal digestibility of CH(2)O was greater when pigs were fed the fermented than nonfermented diets (86.5 vs. 84.5%, respectively; P<0.001). Fermentation reduced (P<0.0001) the fecal excretion of DM, OM, and protein in pigs fed the barley diet, but not when fed the wheat-based diet (P=0.305). Fermentation had no effect (P=0.243) on the fecal digestibility of nonstarch polysaccharides in either of the cereals but their digestibility was 10.0% greater (P<0.001) in pigs fed wheat than the barley-based diets. In conclusion, fermentation of cereal before feeding altered the dietary composition and influenced flow and composition of polysaccharides and other macronutrients at the ileum and in feces to a larger extent for barley than wheat.     

Effects of a high-fiber diet and frequent feeding on behavior, reproductive performance, and nutrient digestibility in gestating sows

A study was conducted to determine the effects of feeding a corn-soybean meal (control) diet vs. a corn-soybean meal-40% soybean hulls (high fiber) diet, as well as the frequency of feeding (once vs. twice daily), on the welfare and performance of gestating sows. Two hundred thirty-nine mixed-parity sows were assigned to a 2 x 2 factorial arrangement of treatments. Sows fed once daily received their entire meal at 0730, whereas sows fed twice daily received one-half of their feed allotment at 0730 and the other half at 1430. The behavior of 68 focal sows (> or = 16 sows per treatment combination) was observed on d 1 postweaning, and on d 40 and d 80 of gestation. The percentage of time standing, lying, sitting, feeding, inactive, and performing stereotypic behaviors was determined. Saliva samples were collected to determine cortisol concentrations. Sow BW and backfat depth were determined on d 0, 40, and 80 of gestation, within 24 h of farrowing, and at weaning. An energy and nitrogen digestibility study was conducted using 36 sows assigned to each of the 4 treatment combinations. Over a 24-h period, the sows fed the high-fiber diet spent less time lying (P < 0.05) than the sows fed the control diet. The frequency of feeding did not affect sow behavior measured over a 24-h period. During mealtimes, sows fed the high-fiber diet spent more time feeding (P < 0.05) than sows fed the control diet. Feeding the high-fiber diet did not affect stereotypic behavior measured over 24 h or during mealtimes. Neither diet nor feeding frequency affected salivary cortisol concentration. Sows fed the high-fiber diet gained less BW and lost backfat (P < 0.05) during gestation compared with sows fed the control diet, whereas sows fed once daily gained less BW and lost backfat (P < 0.05) compared with sows fed twice daily. Sows fed the high-fiber diet had fewer pigs born (P < 0.05) compared with sows fed the control diet. Feeding frequency had no effect on size or weight gain of litters. Sows fed the high-fiber diet exhibited lower digestibility of DM, energy, and N (P < 0.05) compared with sows fed the control diet. Feeding a high-fiber diet utilizing soybean hulls or increasing feeding frequency did not enhance the welfare of sows by reducing stereotypic behaviors nor did it improve reproductive performance.     

Absorption of carbohydrate-derived nutrients in sows as influenced by types and contents of dietary fiber

The current investigation was undertaken to study the absorption and plasma concentration of carbohydrate-derived nutrients [glucose, short-chain fatty acids (SCFA), and lactate] and the apparent insulin production in sows fed diets containing contrasting types and contents of dietary fiber. Six sows were fed 3 experimental diets, low fiber (LF; 177 g of dietary fiber and 44 g of soluble fiber/kg of DM), high soluble fiber (HF-S; 429 g of dietary fiber and 111 g of soluble fiber/kg of DM), and high insoluble fiber (HF-I; 455 g of dietary fiber and 74 g of soluble fiber/kg of DM), in a repeated crossover design. Variations in dietary concentration and solubility of dietary fiber were obtained by substituting starch-rich wheat and barley in the LF diet with dietary fiber-rich co-products (sugar beet pulp, potato pulp, pectin residue, brewers spent grain, pea hulls, and seed residue, which have distinct physicochemical properties). The main carbohydrate component of the LF diet was starch and nonstarch polysaccharides (cellulose and noncellulosic polysaccharides) for the 2 high dietary fiber diets. Consumption of the LF diet resulted in increased and rapid glucose absorption at 0 to 4 h postfeeding. With the HF-I diet, the glucose absorption pattern was similar but at a decreased rate, whereas it was decreased and delayed with the HF-S diet (diet, P < 0.001; time, P < 0.001). These differences were also reflected in the insulin response. The quantitative absorption of SCFA at 0 to 10 h postfeeding was greater when feeding the HF-S diet compared with the LF diet (P < 0.001) and intermediate when feeding the HF-I diet (P < 0.001). The study showed that feeding the high dietary fiber diets resulted in a increased and more uniform uptake of SCFA than when feeding the LF control. Moreover, the HF-S diet reduced diurnal variation in glucose and insulin concentrations.     

Neutral detergent fiber concentration in corn silage influences dry matter intake, diet digestibility, and performance of Angus and Holstein steers

Twelve Angus (237 +/- 13 kg) and twelve Holstein (235 +/- 15 kg) steers were used to determine whether corn silage-based diets with different NDF levels influence DMI to a similar extent in Angus and Holstein steers and as body weight of the steers increase. Steers were randomly assigned to individual slatted-floor pens and used in a crossover design consisting of six 14-d periods. Experimental diets contained corn silage from a normal hybrid (low-fiber; LF) and its male-sterile counterpart (high-fiber; HF) and were alternated each period. The LF and HF diets contained 33.8 and 50.8% NDF, respectively. The HF diet decreased (P < 0.01) overall steer mean DMI 14.0% relative to LF, with mean differences increasing as steers increased in BW (P < 0.01). Feeding the HF diet also reduced ADG by an average of 13.8% relative to the LF diet (P < 0.01). Holstein steers consumed 14.4% more DM and gained 14.3% faster (P < 0.01) than Angus steers. There was a fiber level x breed-type interaction (P = 0.08) for efficiency of gain. Angus steers receiving the HF diet had greater efficiency of gain than Angus steers consuming the LF diet; however, Holstein steers consuming the LF diet had greater efficiency of gain than those receiving the HF diet. The HF treatment reduced total-tract digestibility of DM and GE by 4.6 and 4.5%, respectively (P < 0.01), and decreased DE intake by 20.5% (P < 0.01) but increased apparent totaltract digestibility of NDF and ADF (9.4 and 8.4%, respectively; P < 0.01). Holstein steers had similar digestibility of DM and GE (P > 0.10) but had greater DE intake (P < 0.01) compared to Angus steers. There were fiber level x breed-type interactions for total-tract digestibility of NDF and ADF (P < 0.06). The difference in DM digestibility was negatively associated with the difference in DMI (r2 = 0.23; P < 0.01) for LF minus HF within Angus steers, but not within Holstein steers (P = 0.42). Total-tract digestibility of NDF and ADF was 4.1 and 3.4% lower for the HF diet but was only 1.1 and 0.6% lower for the LF diet when fed to Holstein compared to Angus steers. Results from this trial demonstrate that high-NDF corn silage-based diets reduced intake of both Angus and Holstein steers, and this reduction in DMI continued as steers increased in BW from 235 to 330 kg. Breed differences were also noted for digestible energy intake as influenced by fiber level.     

Sites of nutrient digestion in growing pigs: effect of dietary fiber

The impact of dietary fiber on fecal digestion is well-known and provides a comprehensive approach toward nutrient digestibility and availability. Little quantitative information is available on digestion of fiber in the different segments of the gastrointestinal tract (GIT). The objectives of this study were to obtain a method allowing the quantification of the digestive process in different segments of the GIT and to study the impact of dietary fiber on nutrient digestibility. Six barrows (average initial BW of 30 kg and fitted with a simple T-cannula at the proximal duodenum and caudal ileum) were used in a replicated 3 x 3 Latin square design. In each period, pigs were offered 1 of 3 diets differing in fiber content (low, medium, and high). Differences in fiber content were created by replacing wheat and barley with wheat bran. Titanium dioxide was included in the diet as an indigestible marker to determine the apparent digestibility coefficients in different segments of the GIT. The apparent digestibility of ash, CP, DM, and OM increased in the different segments of the GIT. Duodenal digestibility coefficients were negative for ash (e.g., -39.9% for the medium- and high-fiber diets), indicating important endogenous mineral secretions by the stomach and digestive glands. The duodenal digestibility of other nutrients and OM were positive but close to zero and numerically lower in the diets with the greater fiber contents. The fiber content in the diet did not affect the apparent ileal digestibility of nutrients. Increasing the fiber content in the diet affected the fecal digestibility of CP, ether extract, and energy (P < 0.01). The method used for studying sites of digestion in the digestive tract provides promising results, but it is limited due to the high variability that is likely caused by sampling limitations and variation between animals.     

High-fiber diets in pregnant sows: digestive utilization and effects on the behavior of the animals

Twelve pregnant, multiparous sows were assigned during gestation to three dietary treatments in a 3 x 3 Latin square design to evaluate the effect of increasing levels of crude fiber (CF): a conventional diet low in CF (L, 15.8 MJ DE/kg of DM, 3.3% CF), a diet with a medium level of CF (M, 14.4 MJ DE/kg of DM, 10.6% CF), and a high-fiber diet (H, 12.9 MJ DE/kg of DM, 18.1% CF). The daily feed supply was adjusted to provide the same 33.4 MJ of daily digestible energy (2.4, 2.7, and 3.0 kg/d for diets L, M, and H, respectively). Over the day, a shorter time standing was spent when sows received the H diet (291 min/d) compared with the L (363 min/d) and M diets (324 min/d). Duration of feeding was longer with the high-fiber diet. Mastication represented the main part of the feeding activity in sows fed the H diet (56%) and was reduced with the M and L diets (40% and 25%, respectively). Feeding rate increased when fiber level decreased (67, 120, and 152 g/min for the H, M, and L diets, respectively). Feeding the fibrous diet reduced the incidence of nonfeeding oral behaviors. These results show that high-fiber diets can reduce apparent feeding motivation of pregnant sows and, thus, improve the welfare of sows subjected to feed restriction.     

Adaptation to the digestion of nutrients of a starch diet or a non-starch polysaccharide diet in group-housed pregnant sows

A trial was conducted with twenty group-housed pregnant sows to study the adaptation in nutrient digestibility to a starch-rich diet or a diet with a high level of fermentable non-starch polysaccharides (NSP) during a time period of 6 weeks. The starch-rich diet was primarily composed of wheat, peas and tapioca, whereas soya bean hulls and sugar beet pulp, which both are highly fermentable NSP sources, were used to formulate the NSP-rich diet. The starch-rich diet and the NSP-rich diet were formulated to contain different levels of starch (298 vs. 78 g/kg) and fermentable NSP (100 vs. 300 g/kg), but a similar level of net energy (NE) (8.36 MJ/kg). The trial consisted of a 1-week adaptation period followed by a 5-week collection period. Weekly apparent faecal digestibilities of dry matter (DM), crude protein (CP), crude fat, ash and NSP were measured by using the acid-insoluble ash marker method. Apparent faecal digestibilities of DM and organic matter (OM) of both diets were similar. Faecal digestibility of CP and crude fat was lower (p < 0.001) whereas that of NSP was higher (p < 0.001) for sows that received the NSP-rich diet. Calculated NE values of both diets were similar. Sows fed the NSP-rich diet produced faeces that contained a lower (p < 0.001) DM content compared with sows that were fed with the starch-rich diet. The quantity of dry faeces was the same on both diets, therefore total faeces production (as-is basis) was higher (p < 0.01) for the sows fed the NSP-rich diet. During the 5-week collection period, no changes were observed in the digestibility of DM, OM and NSP in the NE value of the diets. Digestibilities of CP and fat, however, were lower in week 1 (p < 0.05) compared with weeks 2-5 for both diets. The DM content of the faeces and the quantity of dry faeces did not change from weeks 1-5. Diet by time interaction was not observed for any of the response variables indicating that sows adapt as quickly to a diet with a high level of fermentable NSP as to a starch-rich diet. The present trial shows that, with regard to digestibility of nutrients, pregnant sows completely adapt to a NSP-rich diet (i.e., NSP from sugar beet pulp) in 2 weeks and that the time period necessary to adapt to a starch-rich diet or a diet with a high level of fermentable NSP is similar.     

Effect of Dietary Fibre on Digestibility and Energy Metabolism in Pregnant Sows

This study was undertaken to provide information on the effect of two levels of dietary fibre (DF) [184 vs. 407 g DF kg^-1 dry matter (DM)] on the digestibility of nutrients and energy metabolism in pregnant sows during different stages of pregnancy. The amount of DF in the high-fibre diet was supplied by dried sugar beet pulp (20%) and oats, wheat bran and grass pellets. The intake of metabolizable energy (ME) was similar for both the low-fibre and the highfibre diet, with an average daily intake of 30.74 MJ. Digestibility of DM, organic matter, protein, fat and energy was significantly decreased by a high DF level, but no effect of the diets was observed on the stage of pregnancy. A high fibre level significantly increased the digestibility of DF, indicating that fibre from sugar beet pulp is more fermentable than fibre from cereals. Protein utilization increased during the pregnancy, but at a very low level, indicating that the protein level in diets for pregnant sows could be lower. Inclusion of extra DF in the diet significantly increased the amount of energy excreted as CH₄. Heat production was affected by diet, although not significantly (28.77 vs. 29.72 MJ day^-1 in the low-fibre and highfibre diets, respectively). The utilization of ME for energy retention was lower for the high-fibre diet as a result of increased hind-gut fermentation. There was similar relation between the net energy of the standard and the high-fibre diet either calculated using the official Danish feed evaluation (0.77) or experimental estimated value (0.81).     

Standardized ileal protein and amino acid digestibility by growing pigs and sows

Experiments were conducted to determine the effect of the physiological condition of swine on standardized ileal digestibility coefficients (SID). The apparent ileal digestibility coefficients were determined for crude protein and amino acids in six feed ingredients (corn, barley, wheat, soybean meal, canola meal, and meat and bone meal) in growing pigs and in gestating and lactating sows. Growing pigs and lactating sows were given free access to their diets, whereas gestating sows were allowed to consume only 2 kg of feed daily. The nonspecific (basal) endogenous losses of protein and amino acids were determined under similar feeding regimens after feeding a protein-free diet. The SID for crude protein and amino acids were calculated by correcting the apparent ileal digestibility coefficients for the nonspecific endogenous losses of protein and amino acids. With a few exceptions, there were no differences (P > 0.05) in the SID for crude protein and amino acids between growing pigs and lactating sows. Overall, gestating sows had higher (P < 0.05) SID for crude protein and all amino acids, except for tryptophan and aspartate, compared with growing pigs. Likewise, the SID of most amino acids obtained by gestating sows were higher (P < 0.05) than those obtained by lactating sows. Interactions (P < 0.05) between animals and diets were observed for gestating sows compared with growing pigs as well as gestating sows compared with lactating sows. As a consequence, it is not possible to extrapolate data from one feed ingredient to another. On most occasions, the lowest SID among the indispensable amino acids was calculated for threonine, valine, and lysine. It is concluded that gestating sows fed 2 kg of feed per day have higher standardized digestibility coefficients than do growing pigs and lactating sows given free access to their diets. This difference may be due to differences in daily feed intake rather than to the physiological status of the animals.     

Neutral detergent fiber concentration of corn silage and rumen inert bulk influences dry matter intake and ruminal digesta kinetics of growing steers

Corn silage with high NDF concentration has the potential to reduce DMI because it has a greater filling effect in the rumen than low-NDF corn silage. Our objective was to determine whether ruminal fill influences DMI to the same extent with low- or high-NDF corn silage-based diets. Eight ruminally cannulated Holstein steers (198 +/- 13 kg) were randomly assigned to a 2 x 2 factorial arrangement of treatments in a replicated 4 x 4 Latin square design with 16-d periods. Treatments were diets containing corn silage from a normal hybrid (low-fiber; LF) or its male-sterile isogenic counterpart (high-fiber; HF), offered for ad libitum consumption to steers with or without rumen inert bulk (RIB). The LF and HF diets contained 33.8 and 50.8% dietary NDF, respectively. Rumen inert bulk was added at 25% of pretrial ruminal volume in the form of plastic-coated tennis balls filled with sand to achieve a specific gravity of 1.1 and a total volume of 7.5 L. No fiber level x inert bulk interactions were detected for DMI or NDF intake (P > 0.10), suggesting that DMI was limited to the same extent by physical fill at both levels of dietary fiber. Addition of RIB decreased DMI by an average of 10.7%, which was 65.5 g/L of added bulk. The HF diet depressed DMI by an average of 15.5%, increased NDF intake 27.1%, and reduced ruminal NDF turnover time by 21.0% compared to the LF diet (P < 0.01), with no effect on ruminal volume or amount of NDF in the rumen (P > 0.10). Addition of RIB also reduced ruminal NDF turnover time and amount of NDF in the rumen (11.8% and 20.7%, respectively; P < 0.01), with no change in ruminal digesta volume (P > 0.10). The HF treatment decreased digestibility of DM and GE (5.5 and 5.7%, respectively; P < 0.01) but increased NDF digestibility (10.4%; P < 0.01) compared to LF. Rumen inert bulk had no effect on digestibility of DM, NDF, or GE (P > 0.10). The lack of reduction in digesta volume with addition of inert fill suggests that DMI of light-weight steers receiving corn silage-based diets within a wide range of NDF concentrations was not regulated by ruminal distension alone.     

Low-quality roughages in high-concentrate pelleted diets for sheep: digestion and metabolism of nitrogen and energy as affected by dietary fiber concentration

Two trials were conducted to evaluate effects of, and interactions between, level and source of fiber in the diet on ruminal environment, microbial protein synthesis, nutrient digestion and flow of digesta through the gastrointestinal tract of multiple-fistulated sheep (trial 1; 4 X 4 Latin square design) and on ruminal, digestive and metabolic characteristics of early-weaned lambs (trial 2; randomized complete block design; 3 periods). All diets tested were pelleted and were formulated to contain either 39% or 25% neutral detergent fiber (NDF), with corncobs or cottonseed hulls (CSH) as the major NDF (roughage) sources. In trial 1, dry-matter (DM) and organic-matter (OM) digestibilities were not different (P greater than .05) among treatments. Digestibility of NDF was higher (P less than .05) with high-fiber. Bacterial N synthesis (g N/kg OM truly digested) was not different (P greater than .05) among treatments. Molar proportion acetate was higher (P less than .05) and molar proportion propionate lower (P less than .05) when sheep were fed high-fiber diets. In trial 2, apparent DM digestibility was higher (P less than .05) for lambs fed diets containing corncobs. Energy digestibility was higher (P less than .05) at the low-fiber level and for lambs fed diets containing corncobs. Apparent NDF digestibility by lambs was higher (P less than .05) at the high-fiber level and for lambs fed diets containing corncobs. Nitrogen retained (percentage of N intake) was higher (P less than .05) for lambs fed diets containing CSH. Ruminal pH and molar proportion acetate were higher (P less than .05) and molar proportion propionate lower (P less than .05) for lambs fed high-fiber diets. Although responses to corncob vs CSH inclusion in high-energy pelleted diets differ, both roughages are effective as fiber sources in sheep diets.     

Increased fat and polyunsaturated fatty acid content in sow gestation diet has no effect on gene expression in progeny during the first 7 days of life

The ‘developmental origins of health and disease’ hypothesis proposes not only that we are what we eat, but also that we could be what our parents ate. Here, we aimed to improve health and performance of young piglets via maternal diets based on the hypothesis that maternal nutritional interventions change metabolic programming in piglets, reflected by differential gene expression early in life. Therefore, sows were fed either a regular diet, based on barley, wheat and wheat by‐products, sugar beet pulp, palm oil and oilseed meal, or a high‐fat (HF) diet consisting of the regular diet supplemented with an additional amount of 3.5% soybean oil and 1% fish oil at the expense of palm oil and wheat. Performance results, physiological parameters and gene expression in liver of piglets and blood of piglets and sows at day 7 after farrowing from both diet groups were compared. The HF diet tended to enhance growth rate of the offspring in the first week of life. No significant differences in gene expression in liver tissue and blood could be detected between the two groups, neither with whole‐genome microarray analysis, nor with gene specific qPCR analysis. In this study, the feeding of a high‐fat diet with increased amounts of polyunsaturated fatty acid (PUFA) to gestating sows under practical farm settings did not induce significant changes in gene expression in sows and offspring.     

Effects of dietary fiber on performance of multiparous lactating sows in a tropical climate

Sixty-two multiparous Large White sows were used to determine the effect of dietary fiber level on lactation performance according to season under conditions of a humid tropical climate. This experiment was conducted in Guadeloupe (West French Indies, lat 16 degrees N, long 61 degrees W) between October 1999 and January 2001. Two seasons were distinguished a posteriori from climatic measurements parameters continuously recorded in the farrowing room. During the warm season, ambient temperature and relative humidity averaged 25 degrees C and 86.8%, respectively. The corresponding values for the hot season were 27.5 degrees C and 83.5%. Experimental diets fed during lactation were a control diet (C; 14% neutral detergent fiber) and a high-fiber diet (HF; 20% neutral detergent fiber) obtained by substitution of wheat middlings by wheat bran. The two diets were formulated to provide the same ratios between essential amino acids and lysine and between lysine and net energy. No interaction between season and diet composition was found for all criteria studied. Over the 28-d lactation, average daily feed intake (ADFI) was lower and body weight loss was higher (P < 0.001) during the hot season compared to the warm season (3,447 vs 4,907 g/d and 33 vs 17 kg, respectively). The number of stillborn piglets was higher (P < 0.05) during the hot season than during the warm season (2.0 vs 1.1 piglets, respectively). Litter growth rate and mean BW of piglets at weaning were reduced (P < 0.01) during the hot season vs the warm season (2.1 vs 2.3 kg/d and 7.7 vs 8.3 kg, respectively). The ADFI was similar for both diets and digestible energy (DE) intake tended to be lower (P = 0.06) with the HF diet (54.9 vs 59.3 MJ of DE/d for C sows) in relation with its lower DE concentration. The body weight loss was greater (P < 0.01) for HF sows than for C sows (30 vs 21 kg). Compared with the C diet, the HF diet increased (P < 0.05) litter growth rate and piglet body weight at weaning (2.3 vs 2.1 kg/d and 8.3 vs 7.7 kg/d for HF vs C, respectively). Season and diet composition did not affect the weaning-to-estrus interval. In conclusion, the hot season in humid tropical climates, which combines high levels of temperature and humidity, has a major negative effect on the performance of lactating sows.