J. Gasa

Rumen digestion and urinary excretion of purine derivatives in response to urea supplementation of sodium-treated straw fed to sheep.

The present study examined the effect of urea-N supplementation of a N-deficient diet on digestion and metabolism in the rumen. Five Rasa Aragonesa ewes, each fitted with a rumen cannula, were offered alkali-treated barley straw ad lib. alone or supplemented continuously via the cannula with four levels of urea-N (3, 6, 9 and 12 g/d). Rumen NH3 concentrations increased in response to urea infusion (6-128 mg/l; P < 0.001). At the highest level of rumen NH3 concentration there was a significant increase, compared with the unsupplemented treatment, in dry matter (DM) intake (846-1206 g/d; P < 0.001) and apparent digestibility of DM (0.38-0.43), organic matter (0.38-0.45) and neutral-detergent fibre (0.41-0.49; P < 0.01). Rumen outflow rates of particulate matter and potential DM disappearances, assessed using nylon bags, were not affected by the experimental treatments, although fractional rate of DM disappearance increased significantly with increasing levels of urea infusion (2.4-4.6 per h). Urinary excretion of total purine derivatives increased with N supplementation, although the response was exclusively due to an increase in allantoin excretion (26.9-66.4 mg/kg live weight (W)0.75 per d; P < 0.001). Xanthine, hypoxanthine and uric acid excretion rates were constant, averaging 1.8 (SE 0.17); 5.4 (SE 0.21) and 7.2 (SE 0.36) mg/kg W0.75 per d respectively. The maintenance of a minimum rumen NH3 concentration (approximately 50 mg/l) was necessary to avoid significant reductions in DM intake and fermentation rate. Higher levels, however, may further increase microbial N flow at the duodenum, as suggested by the response in urinary allantoin excretion over the range of rumen NH3 concentrations.

Effect of dietary level of protein and fiber on the productive performance and health status of piglets.

To study the interaction between the levels of protein and fiber on the productive performance and health status of piglets, ninety-six 35-d-old piglets (9.11 +/- 0.60 kg of BW) were placed in 32 pens of 3 animals each and allotted to 4 dietary treatments for 21 d. The 4 diets were based on rice, dairy products, and soybean meal in a 2 x 2 factorial arrangement of treatments, with 2 levels of CP (15.4 vs. 19.4%, as-fed basis) and 2 levels of dietary fiber [DF; low fiber (LF) 5.3% NDF and high fiber (HF) 7.15% NDF, as-fed basis]. The HF diet was developed by supplementing the basal diet with 40 g/kg of wheat bran and 20 g/kg of sugar beet pulp. Animal performance was obtained weekly with samples of feces collected for microbiology on the first and the last experimental day and scored from 1 (liquid) to 4 (hard). On the last day, 1 pig from each pen was sampled for blood analyses of the acute-phase protein, major acute-phase protein of pigs (PigMap) and subsequently killed to register the digestive tract weight (including contents) and colon histology. Pigs fed the HF diets had greater ADG (390 vs. 457 g; P < or = 0.001) and large intestine weight (4.4 vs. 5.4% of BW; P < or = 0.05). This coincided with a greater (P < or = 0.05) short-chain fatty acid concentration (especially of acetic and butyric acids), a decrease in Escherichia coli counts (7.77 vs. 6.86 log of cfu/g of feces, P < or = 0.05), and an increase in the ratio of lactobacilli:enterobacteria (0.76 vs. 1.37, P < or = 0.05). However, CP level did not modify the productive performance, but 20% CP increased P < or = 0.05) the relative weight (% of BW) of the small (6.5 vs. 7.7) and large intestine (3.8 vs. 4.3). In the large bowel, the 20% CP diet increased the numbers of goblet cells (4.6 vs. 5.4/100 microm; P < or = 0.05) and reduced the numbers of intraepithelial lymphocytes (1.8 vs. 1.3/100 microm; P < or = 0.05). In relation to health status, increasing DF was dependent of the dietary CP content. Supplementing the 16% CP diet with DF reduced the fecal score and increased the antibiotics interventions, whereas the opposite was the case in the 20% CP diet. Pigs fed the 20% CP diet showed decreased (P < or = 0.05) PigMap concentrations than pigs fed 16% CP diets. As a whole, CP showed major effects on the gastrointestinal weight and gut barrier integrity, whereas DF increased the productive performance and promoted major changes in the microbial colonization and fermentation variables.

Comparative digestibility and lipogenic activity in Landrace and Iberian finishing pigs fed ad libitum corn- and corn–sorghum–acorn-based diets

Forty-eight finishing castrated male pigs (24 Iberian and 24 Landrace; 88.4 kg LW) were fed two diets differing in main carbohydrates sources, corn- (Diet C) or corn–sorghum–acorn (Diet A). After 28 days of experimental period, 24 animals (six per treatment) were slaughtered and digesta and carcass sampled to study digestion and lipogenesis activity. Iberian pigs showed a higher voluntary feed intake than Landrace pigs (3.5 vs. 2.7 kg/day; P<0.01), but no significant differences in the daily weight gain. Between diets, no significant differences were observed in the production data. However, the whole-tract digestibility was significantly lower with Diet A than with Diet C for OM, CP and monosaccharides. Whole-tract apparent digestibility of Iberian pigs was also significantly lower than of Landrace (P<0.01), especially for those animals fed Diet A. As a result of feed intake and digestibility coefficients, Iberian pigs showed a higher intake of digestible OM (2910 g/day) than Landrace (2310 g/day), which was associated with higher (P<0.05) backfat thickness, muscle fat content and lipogenic enzyme activities. Lipogenesis was not broadly influenced by the dietary treatments, except a significant decrease in the intermuscular adipose tissue with diet A. We conclude that digestibility and lipogenic enzyme activities were markedly influenced by the animal breed and to a lesser extent by the diet.

Increased sow nutrition during midgestation affects muscle fiber development and meat quality, with no consequences on growth performance.

Pregnant sow nutrition has potential effects on the muscle fiber development of progeny in utero. A total of 199 Landrace x Large White sows from parities 0 to 6 and their offspring were used to evaluate the effects of increasing the feeding amount during midpregnancy on the muscle tissue, growth performance, and meat quality of the progeny. The experiment was divided into 2 study replicates, and in each replicate, sows were assigned to 1 of the 2 treatments: 1) sows in the control group (C sows) were fed 2.5 to 3.0 kg/d (feed: 12.1 MJ of ME/kg and 0.62% lysine) throughout gestation; and 2) sows in the high group (H sows) received an extra feed allowance of 1.5 kg/d for gilts and 2.0 kg/d for multiparous sows above the C amount from d 45 to 85 of gestation (period of secondary muscle fiber formation). Sow backfat was recorded on d 40 and 85 of gestation. Sow performance (litter size and piglet BW) at farrowing and on d 18 of lactation was measured. At weaning, pigs were divided into 5 BW groups/treatment, and progeny growth performance was measured during the nursery (n = 958) and the growing-finishing (n = 636) periods. At slaughter, carcass and meat quality traits (lean content, main cut weight, pH, Minolta color, and drip loss) were recorded from the second lightest group at weaning (BW group 4; n = 90), and samples from the longissimus thoracis muscle were taken to study muscle fiber characteristics (n = 70). The extra nutrition from d 45 to 85 of gestation did not lead to differences in litter size or piglet BW at farrowing and on d 18 of lactation. Pigs born to H mothers had fewer muscle fibers and fewer estimated primary and secondary fibers than did pigs born to C mothers (P < 0.05). However, postnatal growth performance was not consistently affected by the maternal treatment. The smaller number of muscle fibers found in the H group of pigs was associated with fewer type IIB fibers (P < 0.05) with greater cross-sectional areas (P < 0.10), which might be related to the significantly greater meat pH at 24 h postmortem and the smaller L* (lightness) values recorded in the H group of pigs. Results from the present study confirm the existence of effects of maternal nutrition on fetal development, at least in terms of muscle tissue development and meat quality, although with no beneficial effects were found for the postnatal growth performance of the progeny.

Large bowel fermentation of maize or sorghum-acorn diets fed as a different source of carbohydrates to Landrace and Iberian pigs

Twenty-four finishing pigs (twelve Iberian and twelve Landrace) were used in a growing and slaughtering experiment. Animals were fed two diets differing in their ingredients, maize (diet C) or sorghum-acorn (diet A). At an average weight of 107.0 kg pigs were slaughtered and hindgut digesta sampled to study the effect of breed and diet on large bowel fermentation. Flows of digesta to the hindgut compartment were estimated based on an indigestible flow marker (Cr2O3) and were higher in Iberian than in Landrace pigs (P<0.001), and higher in animals fed diet A than diet C (P=0.07). The higher flows in Iberian pigs were mainly associated with a higher voluntary feed intake (3.50 v. 2.70 kg/d, P<0.01) and lower ileal digestibility of NSP (-12.8 v. 47.8, P<0.01). Differences between diets were mainly associated with a lower ileal digestibility of starch from diet A (89.2 v. 96.9 %, P=0.06), although no differences in the resistant starch content were observed in vitro. Fermentation of different carbohydrates through the large bowel showed that NSP-glucose had lower digestibility in Iberian than in Landrace pigs (62.5 v. 94.2 %, P<0.001), but no differences were observed in starch, or other NSP-fibre fractions (arabinose, xylose and galactose). The type and amount of carbohydrates reaching the large bowel were related to the diet but also to breed, and promoted differences in the fermentative activity associated with different volatile fatty acid patterns and changes in microbial enzymic activity.

Effect and interaction between wheat bran and zinc oxide on productive performance and intestinal health in post-weaning piglets.

The inclusion of fibre has been studied as an alternative to antimicrobials in weaning pig diets, while ZnO is used as an effective method to prevent post-weaning diarrhoea. However, it has not been investigated to what extent these two strategies interact with each other. The present study was designed to evaluate the effects of including wheat bran (WB) and ZnO alone or combined in the diet of early-weaning pigs on productive performance and microbial activity in the gastrointestinal tract (trial 1). A total of sixty-four piglets were distributed in a 2 × 2 factorial combination of two levels of WB (0 v. 40 g/kg) and ZnO (0 v. 3 g/kg) in the diet. The inclusion of ZnO in the diet improved the feed intake and growth of the animals and reduced the incidence of diarrhoea. The inclusion of WB increased SCFA concentrations and decreased Escherichia coli counts. However, simultaneous incorporation of WB and ZnO increased E. coli counts. Two in vitro trials were also designed to clarify hypotheses derived from the in vivo test: (1) the ability of WB and other fibre sources to bind E. coli in vitro (trial 2) and (2) the in vitro interactions between WB and ZnO with respect to E. coli growth (trial 3). We can conclude that incorporation of WB in the diet improved gut health by modulating the activity and composition of the microbial population. The negative interaction between WB and ZnO raises the interest of considering the inclusion of phytase enzymes to reduce the therapeutic levels of ZnO in post-weaning diets.

Enzymes (β-glucanase and arabinoxylanase) and/or sepiolite supplementation and the nutritive value of maize-barley-wheat based diets for broiler chickens.

1. Two experiments were conducted to study the effects of crude enzyme preparations ( β -glucanase and arabinoxylanase) and/or 20 g/kg Sepiolite (Exal®) on the performance and nutrient digestion of broiler chickens fed on maize-barley-wheat based diets. 2. In experiment 1, enzymes improved daily bodyweight gain (by 14%; P <0.001) and food:gain ratios (8%; P <0.001). Sepiolite improved bodyweight gain on the diets not supplemented simultaneously with enzymes (by 6% in 21-d-old chickens, P <0.05) but reduced it for enzymes-supplemented diets. Changes in productive performance with both additives were associated with changes in diet digestibility and nitrogen balance. 3. In experiment 2, enzyme supplementation reduced viscosity in jejunum and ileum and the mean retention time of digesta in the gut. Sepiolite inclusion significantly reduced the viscosity of jejunum digesta and modified the retention times of digesta in the gut, depending upon whether enzymes had been added. There was a decreased retention time without enzymes but an increase with enzyme supplementation. 4. Although different mechanisms are presumed for enzymes and sepiolite, both seem to counteract the negative effects of soluble, non-starch polysaccharides (NSP) in the diet by modifying jejunal viscosity and improving organic matter digestibility.

Dietary protein modifies effect of plant extracts in the intestinal ecosystem of the pig at weaning.

The plant extract mixture (XT) used in the present experiment, containing carvacrol, cinnamaldehyde, and capsicum oleoresin, has previously been shown to decrease diarrhea mortality and to modify the intestinal environment of pigs after weaning. However, results obtained among experiments have not been consistent. We hypothesized that dietary protein could be a main factor determining the effect of plant extracts on intestinal environment. Thus, in the present study we assessed the effects of XT in piglet diets with different protein sources and amounts. Pigs weaned at 20 +/- 1 d of age (n = 240) were allocated to 1 of 6 treatments, which followed a factorial arrangement, with 2 amounts (as-fed basis) of the XT (0 and 200 mg/kg) and 3 diets with various amounts of CP and protein sources. Diet FM18 contained 10% of low-temperature fish meal (LT-FM) and a CP level of 18%; diet SBM18 contained 5% of LT-FM plus 9% of full fat extruded soy and a CP level of 18%; and SBM20 diet contained 10% of LT-FM plus 6.3% of full fat extruded soy and a CP level of 20%. Growth performance of the animals was recorded for 14 d, but no differences were detected among treatments. Eight pigs per treatment were killed to examine variables describing aspects of gastrointestinal ecology. For diets containing 18% CP, FM18 and SBM18, XT tended to decrease ileal digestibility of OM (P = 0.064 and 0.071, respectively) and decreased starch digestibility (P = 0.032 and 0.014, respectively). It also reduced villi length (P = 0.003 and 0.013, respectively) and tended to decrease intraepithelial lymphocyte number (P = 0.051 and 0.100, respectively) in the proximal jejunum. The XT inclusion also increased ileal lactobacilli:enterobacteria (P = 0.017) ratio and decreased VFA production in the cecum (P = 0.045) for all diets. A decreased CP level appeared to favor the effects of the studied plant extracts in a positive or negative way depending on the variable measured. The microbial differences produced by XT could be the reason for improved digestive health observed by the authors in stronger challenging conditions (e.g., dirtier environments or long fasting periods after weaning).

Effect of cross-fostering and oral supplementation with colostrums on performance of newborn piglets.

The aim of the experiment was to study the effect on litter performance of two oral supplementation strategies on piglets born weighing 1.35 kg or less (SP; CON: no oral supplementation; COL: supplementation with 15 mL of sow colostrum orally administered to piglets within 4 h after the farrowing was completed). Two levels of cross-fostering strategies, performed 24 h after farrowing, were also studied (HL: litters fixed at 12 piglets, ensuring that less than 50% of the piglets of the litter were SP; LL: litters fixed at 12 piglets, with most of the piglets of the litter being SP; in both cases the aim was to minimize moving piglets from one sow to another as much as possible). The combination of the 2 management strategies described above resulted in a 2 × 2 factorial model. Forty-six litters were used. Litters were allocated to 1 of the 4 treatments: CON-HL, CON-LL, COL-HL, and COL-LL. Piglets were weighed on d 1 and 19 postpartum. Mortality was recorded. On d 4 postpartum, a 2-mL blood sample was obtained from 79 SP piglets born from multiparous sows included in the experiment. To obtain a negative control group, blood samples were obtained on d 4 postpartum from 8 additional SP piglets that were separated from their mothers at birth and bottle fed with milk replacement for 12 h. LL sows had lower within-litter CV of BW at d 1 than HL sows (16.2% vs. 21.9% ± 0.91%; P = 0.003), but they did not differ for litter CV of BW at d 19 (23.2% vs. 23.4% ± 1.72%). At d 19, HL sows had fewer dead piglets per litter than LL sows (0.80 vs. 1.69 ± 0.307; P = 0.022), and COL-HL sows had fewer dead piglets per litter than CON-HL (0.47 vs. 1.14 ± 0.160; P = 0.062). Cross-fostering SP in the same litter did not prevent a litters CV of BW from increasing at weaning. Piglets from the COL group had higher IgG concentration than piglets from the CON group (P = 0.001). However, piglets from the negative control group had lower IgG concentration than those from the COL and CON groups (5.41 ± 2.320 vs. 30.60 ± 1.582 and 21.53 ± 0.951 mg/mL, respectively; P < 0.001 in both cases). Allocating small piglets to the same litter through cross-fostering had a negative effect on mortality and did not improve litter CV of BW at weaning. Colostrum supplementation of SP piglets improved IgG blood level on d 4. In addition, in nonhomogenized litters, colostrum supplementation of SP piglets might be a good management strategy to improve litter performance.

Feeder Use Patterns in Group-Housed Pregnant Sows Fed With an Unprotected Electronic Sow Feeder (Fitmix)

Previous studies on feeder use in group-housed pregnant sows focused on dynamic groups and protected electronic sow feeders (ESF). This study observed 60 pregnant sows, 1st to 8th parity—housed from Day 29 of pregnancy to 1 week before parturition in stable groups of 20 animals, 1 Fitmix feeder per group. Data from 25 nonconsecutive 24-hr feeding cycles showed sows making several visits to the feeder. Literature on conventional ESF indicated shorter daily feeder occupation. Daily feeder occupation per sow decreased over time (p < .001). The study observed maximum feeder activity in the hours following the start of each feeding cycle. During the experiment, there was a relatively stable, quickly established, and maintained feeder order (W > 0.80, p < .001). This highly correlated with dominance rank (r s = 0.80, p < .001). High-ranking sows fed earlier and made as many—but longer—visits as low-ranking sows; thus, they occupied the feeder more time every day (p < .01). Although optimization of the feeder efficiency may take several weeks, Fitmix seems an efficient feeding system for medium-size, stable groups of sows.