A dual marker technique to estimate individual feed intake in young pigs.

Accurate estimation of individual feed intake (FI) of pigs could help better understand the variation in performance between individual animals. We studied dual marker methods to estimate individual FI in pigs. This method is based on the measurement of the ratio between two indigestible markers in faeces. Twelve 6.5-week-old individually housed male pigs were assigned to one of three oral dosing treatments supplying 180 mg of ytterbium chloride (YbCl3)/day and 111 mg of dotriacontane (C32)/day as reference markers, either once (R1), three times (R3) or five times (R5) daily. Pigs were offered a diet containing 0.46 g/kg of chromium chloride (CrCl3) and 0.15 g/kg of hexatriacontane (C36) as in-feed markers. The experiment lasted for 10 days: days -5 to 0: adaptation; days 1-3: dosing of reference marker; days 2-4: total faecal collection. Spot faecal samples were taken on day 3 at 1200 h, 1700 h and on day 4 at 0700 h. Pigs were fed restrictedly three times daily, at 133.6 g/kg BW0.60. Individual measured FI was recorded daily and was compared to predicted FI using the ratio of the dual marker pairs (Yb:Cr and C32:C36), both in total faecal collection and spot samples. Due to unequal variance, R1 pigs were omitted from the statistical treatment comparison. When using total faecal collection samples, the absolute prediction error (APE) (predicted FI minus measured FI) in R3 and R5 pigs was numerically lower than in R1 pigs, regardless of the marker pair used. The APE measured by C32:C36 was numerically lower than measured by Yb:Cr at all frequencies, and significantly (P = 0.039) in R3 pigs (C32:C36: 0.15 ± 0.02 kg/day; Yb:Cr: 0.29 ± 0.04 kg/day). This was related to a larger difference in faecal recovery between Yb and Cr compared with C32 and C36. Daily total faecal collection revealed that for R3 pigs, starting faecal collections 2 days after the onset of provision of the reference marker improved the APE when compared with starting after 1 day. When using C32:C36 to predict feed intake, pooled, but not single spot samples gave similar APEs compared with total faecal collections. Therefore, we recommend dosing the reference marker three times per day for 2 days on days 1 and 2, combined with pooled spot faecal sampling collected on days 3 and 4. In this way, absolute prediction errors of 10%-15% of simultaneously measured intakes of multiple nutrient resources in a complex housing system are feasible using the dual marker technique.

Effects of pre-weaning housing in a multi-suckling system on performance and carbohydrate absorption of relatively light and heavy piglets around weaning.

The low feed intake and stress associated with abrupt weaning in conventional pig farming often result in poor post-weaning performance, which is related to impaired intestinal function. We investigated effects of housing conditions before weaning on performance around weaning of relatively light and heavy piglets. Before weaning, piglets were housed either with five sows and their litters in a multi-suckling (MS) system or in pens with individually housed sows in farrowing crates (FC). After weaning at 4 weeks of age (day 0), 16 groups of four piglets (two light and two heavy litter-mates) were housed under equal conditions in enriched pens. Mannitol (day -5 and day 5) and galactose (day 5) were orally administered as markers for gastrointestinal carbohydrate absorption, and after 20 min a blood sample was taken (sugar absorption test). In addition, BW, feed intake and faecal consistency as an indicator for diarrhoea, were assessed frequently during 2 weeks post-weaning. Pre-weaning housing, weight class and their interaction did not affect post-weaning faecal consistency scores. Weight gain over 2 weeks did not differ between pre-weaning housing treatments, but MS piglets gained more (0.67±0.12 kg) than FC piglets (0.39±0.16 kg) between days 2 and 5 post-weaning, P=0.02), particularly in the 'heavy' weight class (interaction, P=0.04), whereas feed intake was similar for both treatments. This indicates a better utilisation of the ingested feed of the MS piglets compared with the FC piglets in the early post-weaning period. Pre-weaning mannitol concentrations were unaffected by pre-weaning housing, weight class and their interaction. On day 5 post-weaning, however, MS piglets had a lower plasma concentration of mannitol (320 v. 592 nmol/ml, SEM=132, P=0.04) and galactose (91 v. 157 nmol/ml, SEM=20, P=0.04) than FC piglets, regardless of weight class. In conclusion, MS and FC piglets differed in aspects of post-weaning gastrointestinal carbohydrate absorption and in weight gain between days 2 and 5 after weaning, but pre-weaning housing did not affect feed intake, weight gain and measures of faecal consistency over the first 2 weeks after weaning.

Endogenous phosphorus losses in growing-finishing pigs and gestating sows.

An experiment was conducted to determine the effects of diet composition, feeding level (FL), and BW on endogenous phosphorous losses (EPL) using growing-finishing (GF) pigs and sows. After an adaptation period, 48 GF pigs (initial BW 90.5 kg) and 48 just-weaned sows (initial BW 195 kg), both individually housed, were allotted to 12 dietary treatments in a 2 × 3 × 2 factorial arrangement. Treatments were animal type (GF pigs or sows), diet composition (a semipurified starch (STA), inulin (INU), or lignocellulose (CEL) based low-P diet), and FL (2.0 or 3.0 kg/d). Digestibility of DM, OM, CP, crude fat, and carbohydrates (COH), and fecal P excretion (in g/d, mg/kg DMI, and g/(kg BW·d)) were determined using TiO as indigestible marker. Digestibility of OM and COH differed among diets ( < 0.001) and was greatest in both types of pigs fed the STA diet and lowest in those fed the CEL diet. While digestibility of OM and COH was similar in sows and GF pigs that were fed the STA diet and the CEL diet, on the INU diet, sows had, compared with GF pigs, a greater digestibility of OM (92.2 vs. 87.2%) and COH (92.5 vs. 88.4%), respectively. Both BW and FL increased fecal P excretion (g/d). When expressed in mg/kg DMI, P excretion was higher in sows than in GF pigs on the STA diet (498 versus 236 mg/kg DMI), the INU diet (526 vs. 316 mg/kg DMI), and the CEL diet (928 vs. 342 mg/kg DMI). When expressed in mg/(kg BW·d), however, P excretion was similar in GF pigs and sows that were fed the STA diet and in those that were fed the INU diet, whereas it was greater in sows than in GF pigs that were fed the CEL diet (11.6 vs. 7.3 mg/(kg BW·d)). The results of this study indicate that EPL (mg/kg DMI) in pigs substantially increase with increasing BW. Application of EPL (mg/kg DMI) determined in GF pigs may underestimate EPL and therefore P requirements in gestating sows. Moreover, EPL is diet dependent and increases with an increasing content of dietary nonstarch polysaccharides (NSP). The degree of this increase may differ between sows and GF pigs and seems to depend on properties of dietary fiber.

Development of piglets raised in a new multi-litter housing system vs. conventional single-litter housing until 9 weeks of age.

This study compared the development until 9 wk of age of piglets raised in either a multi-litter (ML) system or a conventional single-litter (SL) system. The ML system consisted of a multi-suckling system with 5 sows and their litters before weaning, followed by housing in a pen with enrichment in a group of 40 piglets after weaning. In the SL system, piglets were housed with a crated sow before weaning, followed by postweaning housing in groups of 10 littermates in a standard pen. Fifty litters were used in 5 batches and piglets were weaned at 4 wk of age. Preweaning mortality was higher in the ML system than in the SL system (3.22 ± 0.42 vs. 1.52 ± 0.25 piglets per litter, < 0.01), mainly due to crushing before grouping of litters. Litter size at grouping did not differ between systems. ML piglets showed more feed-directed behavior at 2 wk of age (6.80 ± 0.96 vs. 2.35 ± 0.59, < 0.01), suggesting an earlier start of feed exploration, possibly due to social learning from the floor-fed sows and other piglets. Moreover, before weaning, ML piglets showed less damaging oral manipulation (e.g., tail biting) than SL piglets (1.4 ± 0.2 vs. 3.6 ± 0.3 freq/h, < 0.001), which was likely related to the more enriched environment in the ML system. After weaning, ML piglets ate 81% more feed between d 1 and 2 (0.29 ± 0.02 vs. 0.16 ± 0.03 kg/piglet, < 0.01) and had an 82% higher weight gain until d 5 than SL piglets (1.35 ± 0.21 vs. 0.75 ± 0.17 kg, < 0.05) despite a similar weaning weight (ML: 8.4 ± 0.2 kg, SL: 8.3 ± 0.2 kg). Within the first 2 wk after weaning, ML piglets had a lower fecal consistency score (0.27 ± 0.03 vs. 0.39 ± 0.03, < 0.05), indicating a lower occurrence of diarrhea compared with SL piglets. Over the entire 5-wk postweaning phase, ML piglets had a 24% higher weight gain ( < 0.05) and showed more play behavior (4.0 ± 0.3 vs. 2.8 ± 0.3 freq/h, < 0.05) and less damaging oral manipulation (1.8 ± 0.3 vs. 3.5 ± 0.4 freq/h, < 0.01) than SL piglets. These results are probably explained by a combination of the differences in preweaning development, early postweaning performance, and postweaning environment, with a larger and more diverse social group and more physical enrichment in the ML pen. To summarize, provided that preweaning mortality can be reduced, the ML system seems promising for raising robust piglets with better welfare, indicated by a better preweaning behavioral development, improved transition to the postweaning phase, and better postweaning performance.

A review of sow and piglet behaviour and performance in group housing systems for lactating sows.

Commercial use of group housing systems for lactating sows is limited, but the recent transition to group housing during gestation in the EU may result in a renewed interest in such systems. Therefore, this review aims to identify key factors that may contribute to the success or failure of group housing of lactating sows in comparison with individual housing by describing the variety in group housing systems and discussing animal behaviour and performance compared with individual housing. Group housing systems can be divided in multi-suckling (MS) systems, in which sows are grouped with their litters, and get-away (GA) systems, which include a separate communal area accessible to sows only. These systems differ in many aspects regarding management and layout but, compared with individual housing, generally provide more environmental complexity, more freedom of movement for the sows and more freedom to express behaviours related to, for example, maternal care and social interactions. Group housing poses several risks, such as disrupted nursing and an increased level of crushing during the MS phase, and in the GA systems there is a risk for early cessation of nursing. On the other hand, pre-weaning mingling of litters clearly benefits piglet social development and may improve adaptation to the post-weaning situation. In addition, group-housed sows may show lactational ovulation, which provides opportunities for insemination during an extended lactation period, which benefits the piglets. Gradual transitions in social and physical environment around gestation, farrowing, grouping and weaning seem to be key success factors for group housing systems during lactation. In addition, selection of suitable sows and quality of stockmanship seem important.

A simple amino acid dose-response method to quantify amino acid requirements of individual meal-fed pigs.

Two experiments were conducted to develop a simplified dose-response technique to estimate the Lys requirement of individual, meal-fed growing pigs. In Exp. 1, we studied adaptation processes that occur during such a dose-response study in meal-fed pigs, and in Exp. 2, we studied the accuracy of this simplified technique to estimate changes in Lys requirement estimates of pigs following changes in energy intake. In Exp. 1, the effect of the Lys supply strategy on the Lys requirement was assessed in 14 barrows fed an increasing [low to high (LH)] or decreasing [high to low (HL)] total Lys supply, with total Lys levels varying from 0.36 to 1.06 g/MJ DE in 7 equidistant steps of 4 d each. Urinary urea and ammonia excretion and whole body N turnover were measured. In Exp. 2, the accuracy of the dose-response technique to determine a shift in Lys requirement was assessed in 20 barrows fed at either 2.2 [low energy (LE)] or 2.7 [high energy (HE)] times the energy requirements for maintenance, with total Lys supply decreasing from 1.10 to 0.37 g Lys/MJ DE in 9 equidistant steps of 3 d each. In Exp. 1, a lower increment in protein synthesis, breakdown, and whole body N turnover with increasing dietary Lys supply was observed in LH pigs than HL pigs (P < 0.01) and the estimated Lys requirement was 0.06 g/MJ DE greater (P = 0.01) in LH pigs than HL pigs. These results indicated that pigs at a decreasing Lys supply strategy require less time for metabolic adaptation to a change in Lys supply than those at an increasing Lys supply. In Exp. 2, the estimated Lys requirement was 2.6 g/d greater (P < 0.001) in HE pigs than LE pigs. The variation in AA requirement estimates between individual pigs was low (4.9% in LH pigs and 3.0% in HL pigs in Exp. 1 and 8.1% in LE pigs and 6.0% in HE pigs in Exp. 2). The present studies indicated that a dose-response technique with a decreasing Lys supply in time and a step length of 3 d with urinary N excretion as response criteria provides a simple, accurate technique to quantitatively estimate a change in AA requirements of individual meal-fed pigs.

Farm and management characteristics associated with boar taint.

Pig farms in the Netherlands producing boars have different levels of boar taint prevalence, as assessed by sensory evaluation with the human nose at the slaughter line. With a questionnaire to 152 Dutch pig producers (response rate 59%), farm and management characteristics were identified that are potentially associated with farm-level boar taint prevalence. Lower farm-level boar taint prevalence was associated with a smaller group size, a smaller pen surface per boar, newer housing equipment, not practicing restricted feeding in the last period before delivery, a longer fasting period before slaughter, a higher stocking weight and a lower fraction of boars from purebred dam line sows or from Pietrain terminal boars. These characteristics can be used to develop farm-level intervention strategies to control boar taint. More research effort is needed to establish causal relationships.

An increased feed intake during early pregnancy improves sow body weight recovery and increases litter size in young sows.

This study evaluated the effect of feeding level and protein content in feed in first- and second-parity sows during the first month of gestation on sow BW recovery, farrowing rate, and litter size during the first month of gestation. From d 3 to 32 after the first insemination, sows were fed either 2.5 kg/d of a standard gestation diet (control, n = 49), 3.25 kg/d (+30%) of a standard gestation diet (plus feed, n = 47), or 2.5 kg/d of a gestation diet with 30% greater ileal digestible AA (plus protein, n = 49). Feed intake during the experimental period was 29% greater for sows in the plus feed group compared with those in the control and plus protein groups (93 vs. 72 kg, P < 0.05). Sows in the plus feed group gained 10 kg more BW during the experimental period compared with those in the control and plus protein groups (24.2 ± 1.2 vs. 15.5 ± 1.2 and 16.9 ± 1.2 kg, respectively, P < 0.001). Backfat gain and loin muscle depth gain were not affected by treatment (P = 0.56 and P = 0.37, respectively). Farrowing rate was smaller, although not significantly, for sows in the plus feed group compared with those in the control and plus protein groups (76.6% vs. 89.8 and 89.8%, respectively, P = 0.16). Litter size, however, was larger for sows in the plus feed group (15.2 ± 0.5 total born) compared with those in the control and plus protein groups (13.2 ± 0.4 and 13.6 ± 0.4 total born, respectively, P = 0.006). Piglet birth weight was not different among treatments (P = 0.65). For both first- and second-parity sows, the plus feed treatment showed similar effects on BW gain, farrowing rate, and litter size. In conclusion, an increased feed intake (+30%) during the first month of gestation improved sow BW recovery and increased litter size, but did not significantly affect farrowing rate in the subsequent parity. Feeding a 30% greater level of ileal digestible AA during the same period did not improve sow recovery or reproductive performance in the subsequent parity.

Effects of dietary energy concentration, nonstarch polysaccharide concentration, and particle sizes of nonstarch polysaccharides on digesta mean retention time and gut development in laying hens.

1. From an experiment with 504 laying hens (ISA Brown strain, 18-40 weeks of age), 90 40-week old hens were used for determining digesta mean retention time (MRT) and gut weight development. This experiment comprised 6 dietary treatments according to a 2 × 3 factorial design. Factors were dietary apparent metabolisable energy (AME) concentration (11·8 vs 10·6 MJ/kg), insoluble nonstarch polysaccharides (NSP) concentration (65 vs 134 g/kg), and fine vs coarse particle sizes of added NSP. Titanium recovery in different gut segments was used as an indicator of MRT. 2. Increasing NSP concentration prolonged MRT in the crop (68 vs 34 min) and total foregut (91 vs 57 min) compared with control NSP. Reducing energy concentration prolonged MRT in the colon (26 vs 7 min), and total hind gut (30 vs 9 min), compared with control energy. Overall MRT was not affected by dietary treatments. 3. Increasing NSP concentration increased relative weights of the empty proventriculus-gizzard and its contents by 30% (25·2 vs 19·4 g/kg) and 18% (15·4 vs 13·0 g/kg), respectively, compared with control NSP diets. 4. MRT in the foregut was prolonged as daily insoluble NSP intake increased, and this was more pronounced in hens given coarsely ground NSP, compared with finely ground. A prolonged MRT in the foregut seemed to indicate a higher level of satiety, which may contribute to a lower feather pecking pressure in laying hens.

Performance and energy metabolism in restrictively fed weanling pigs are not affected by feeding either fermented cereals or their end-products.

To study the effects of feeding fermented cereals or just fermentation end-products on performance and energy metabolism, 18 restrictedly fed groups of eight pigs each were assigned to one of three dietary treatments: (i) a liquid control diet (C) containing 40% of a mixture of barley and wheat; or (ii) a liquid diet (F) containing 40% fermented barley and wheat; or (iii) a liquid diet as C with the addition of some important fermentation end-products (FP; organic acids and ethanol) in concentrations similar to those in the fermented F-diet. Energy and nitrogen balances, heat production, and performance traits were measured during two consecutive periods (days 1-5 and days 6-14). There was a considerable increase in average dry matter intake that tended (p = 0.06) to be higher in the FP-group than in the other groups. Apparent fecal digestibility of dry matter, ash, nitrogen and energy during period 2 were not affected (p > 0.1). Averaged over both periods, none of the energy metabolism parameters were affected by the diets (p > 0.1). However, there were diet × period interactions for metabolizable energy-intake (p = 0.07), energy retention (p < 0.05), the respiratory quotient (RQ; p < 0.01) and activity-related heat production (H(ACT,) p = 0.05). Additionally, there were some differences between the diets in the average hourly patterns in RQ and H(ACT). In conclusion, restricted feeding of either 40% fermented cereals nor their fermentation end-products affected performance and energy metabolism traits in weanling pigs. Nevertheless, lower postprandial activity-related heat production by pigs given the fermented cereals suggest a stimulating effect of fermented cereals on short term satiety that was not seen in pigs given fermentation end-products only.

Effects of prefermented cereals or the end products of fermentation on growth and metabolism of enterocyte-like Caco-2 cells and on intestinal health of restrictedly fed weanling pigs.

To unravel the underlying mechanisms that explain the positive effects of prefermented cereals on in vivo gastrointestinal (GI) architecture and function, an in vitro experiment using a human small intestinal epithelial cell model (Caco-2) was performed. A range of dilutions (0% to 10%) of the supernatants of three liquid experimental diets, as well as Na-lactate were used in an in vitro experiment to assess their effect on cellular growth, metabolism, differentiation and mucosal integrity using Caco-2. The experimental diets contained, in addition to a protein rich basal diet (60%), (1) a liquid control diet (C) containing 40% of a mixture of barley and wheat (ratio 3 : 1) or (2) a liquid diet (F) containing 40% prefermented barley and wheat or (3) C with the addition of the fermentation end-products (organic acids and ethanol) in concentrations similar to those in the fermented diet (FP). For F, the mixture of barley and wheat was fermented at 35°C for 48 h. Parallel to the in vitro experiment, 18 groups of eight weanling pigs were assigned to one of the experimental diets during a 14-day in vivo experiment. Each group was fed restrictively. The results of the in vitro experiment showed that the lowest dose of both F- and FP-supernatants had no clear effects on the cell proliferation, but incubation with 5% and 10% of the F- and FP-supernatants decreased the cell numbers at day 19. DNA, RNA, protein and glycoprotein synthesis in differentiated Caco-2 cells were stimulated by incubation with the lower concentrations (0.5% to 2.5%) of F- and FP-supernatants whereas the higher concentrations (5% and 10%) had no effect. Both the F- and FP-supernatants decreased the specific sucrase-isomaltase activity in a dose-dependent manner, but the effects on the specific aminopeptidase activities were less clear. Mucosal integrity initially decreased after incubation with the highest F- and FP-supernatants and started to recover between 24 and 48 h. The results of the in vivo experiment showed no dietary effects (P > 0.1) on GI morphology and brush-border enzyme activities at day 5 or at day 14. Time related changes in GI characteristics followed a normal pattern. In conclusion, the supernatants of diets containing either prefermented cereals or their fermentation end-products clearly modulate cellular growth, metabolism, differentiation and mucosal integrity in an in vitro model, although these effects were not observed in the in vivo characteristics measured in weanling pigs.

Effects of nutrient dilution and nonstarch polysaccharide concentration in rearing and laying diets on eating behavior and feather damage of rearing and laying hens.

An experiment was conducted with 768 non-cage-housed ISA Brown pullets, of which 576 hens were followed during the laying period, to investigate the separate effects of dietary energy dilution and non-starch polysaccharides (NSP) concentration (oat hulls as NSP source) on eating behavior and feather damage. Day-old pullets were allotted to 1 of 6 dietary treatments according to a 3 x 2 factorial arrangement (3 dilution and 2 NSP levels), with 8 replicates (pens) per treatment. At 17 wk of age, pens with hens were allotted to 1 of 8 dietary treatments according to a 4 x 2 factorial arrangement (4 dilution and 2 NSP levels), with 6 replicates per treatment. Compared with 0% dilution level, feed intake of laying hens of 10, 15, and 20% dilution levels increased by 8.4% (9.5 g/hen per d), 16.5% (18.1 g/hen per d), and 20.9% (23.6 g/hen per d), respectively. The ME(n) intake was similar for all dilution levels. Hens fed standard-NSP laying diets had similar insoluble NSP intake for all dilution levels (9.3 g/hen per d). Insoluble NSP intake of hens fed high-NSP laying diets increased from 15.6 g/hen per day (0% dilution) to 18.9 g/hen per day (20% dilution). Providing high- vs. standard-NSP layer diet decreased relative proventriculus contents (1.1 vs. 0.3 g/kg of BW) and increased empty gizzard weight (14.3 vs. 24.4 g/kg of BW). Hens that were fed standard-NSP diets had more feather damage compared with hens fed high-NSP diets (0.58 vs. 0.30 arbitrary units). Increasing the insoluble NSP intake resulted in decreased proventricular weight and increased gizzard weight and its contents, which are indicators of improved functioning of the gut, thereby linearly reducing feather damage. Providing diluted rearing diets increased feed intake from the first weeks of life onwards. It was hypothesized that pullets were increasingly "imprinted" on feed as pecking substrate if dilution level increased. This may decrease feather pecking and could explain the improved feather condition at 49 wk of age when 15% diluted rearing diet was fed.

Low dietary energy concentration, high nonstarch polysaccharide concentration, and coarse particle sizes of nonstarch polysaccharides affect the behavior of feather-pecking-prone laying hens.

An experiment was conducted with 504 non-cage-housed ISA Brown laying hens from 18 to 40 wk of age to investigate the separate effects of dietary energy concentration, nonstarch polysaccharide (NSP) concentration, and particle sizes of added NSP source on the eating behavior, feather-pecking behavior, and hen performance of laying hens. Hens were allotted to 1 of 6 dietary treatments according to a 2 x 3 factorial arrangement, with 7 replicates per treatment. The factors were control and low energy concentration (2,825 vs. 2,540 kcal/kg), control and high NSP concentration (133 vs. 195 g/kg), and fine vs. coarse particle size of the added NSP source in the high-NSP diets. We hypothesized that eating time would be increased by feeding low-energy diets or coarsely ground, high-NSP diets, or both, resulting in reduced feather-pecking behavior, without negatively affecting hen performance. Energy reduction, NSP addition, and coarse grinding of NSP increased eating time by 14.2% (P = 0.001), 17.2% (P < 0.001), and 7.9% (P = 0.075), respectively, compared with the control level of these factors. Addition of NSP decreased eating rate (g/min) by 21.0% (P = 0.010). Layers already performed gentle feather-pecking behavior during the fifth week of the rearing period. Dietary treatments did not affect the maximal level of feather condition scores, but arise of feather damage was delayed by 10 wk in hens fed low-energy, coarsely ground, NSP-rich diets compared with hens fed control diets. Hens fed the control NSP diets showed reduced culling rates, because of less cannibalistic pecking, when energy concentration was decreased (44.1 vs. 13.1%), whereas in the high-NSP diets, culling rate decreased slightly when hens were fed the low-energy diets (31.6 vs. 28.6%; P = 0.071). Hens that were fed the low-energy diets compensated for the 10% reduction in energy concentration by a 9.3% higher maximal feed intake (143.0 vs. 130.8 g/d). Hen performance and BW gain of the hens were not affected by dietary treatments. We concluded that hens that were fed low-energy or high (coarsely ground)-NSP diets spend more time on feed intake, compared with hens that were fed the control diets. As a result, hens in some treatments showed less feather-pecking behavior.

Effect of nutrient dilution on feed intake, eating time and performance of hens in early lay.

1. An experiment with 480 ISA Brown layers was conducted to measure the effect of dietary energy (11.8, 11.2 and 10.6 MJ/kg) and non-starch polysaccharides (NSP) (128, 146 and 207 g/kg) concentration, soluble NSP content (64 and 85 g/kg), particle size distribution of the NSP fraction (fine and coarse) and feed form (mash and crumble) on feed intake, eating time and egg performance of laying hens in early lay (from 18 to 26 weeks of age). Twelve experimental diets were tested, each replicated 4 times. 2. Laying hens in early lay that were fed low- or high-NSP diets were able to compensate for 10% dietary dilution by 9.5 and 4.9% higher feed intakes, respectively. Feeding crumble or coarsely ground mash did not affect feed intake. 3. Eating time of the hens fed the undiluted diets increased over the experimental period from 16.4 to 24.6% of the observation period, but was not affected by sand or grit addition, particle size distribution or feed form. Feeding high-NSP diets increased eating time by 22%. 4. Egg performance and body weight gain of the hens that were fed low-NSP or high-NSP diets were similar or better compared to the undiluted diets, whereas coarse grinding of the diets showed 7 to 10% lower egg performance and weight gain. Egg performance and weight gain were not affected by feed form. 5. It is concluded that hens in early lay, fed energy-diluted diets, by adding sand or grit (low-NSP) or NSP-rich raw materials (high-NSP) to the control diet, were able to increase their feed intake, resulting in energy intake and egg performance comparable to the control group. Supplementing diets with insoluble NSP also decreased eating rate. Prolonged eating time using insoluble NSP could be useful in reducing feather pecking behaviour.

Effects of yeast culture on performance, gut integrity, and blood cell composition of weanling pigs.

An experiment was conducted to determine the effects of yeast culture (YC) and modified yeast culture [YC + cell wall product (CWP) containing mannan oligosaccharides] in pig diets on the performance, gut integrity, and blood cell composition of weanling pigs and to determine whether these dietary supplements could replace antimicrobial growth promoters (AGP) in pig diets. A total of 480 weanling pigs (27 d old and 7.8 +/- 0.1 kg of BW) were assigned to 1 of 4 experimental treatments: 1) diets without AGP or YC (control diet); 2) control + AGP; 3) control + 0.125% YC; and 4) control + 0.125% YC + 0.2% CWP. Piglets were fed experimental diets for 5 wk after weaning. Blood samples were collected from 8 piglets at weaning and from 8 piglets per treatment on d 14 and 35 after weaning for blood cell composition. These piglets were slaughtered for measurement of villous length and crypt depth in the jejunal mucosa and microbial profiling on the intestinal digesta. Average daily gain (P = 0.06) and G:F (P = 0.02) were improved for piglets that were fed the supplemented diets compared with piglets that were fed the control diet. Average daily feed intake was unaffected by dietary treatment. Performance was similar in piglets fed diets supplemented with AGP, YC, and YC + CWP. Blood cell composition, villous length, crypt depth, and microbial composition in the gut were unaffected by dietary treatment, but they were affected by time after weaning. Red blood cells, hemoglobin, hematocrit value, mean cell volume, mean cell hemoglobin, percentage of lymphocytes in the leukocyte population, villous length, and crypt depth were greater (P < 0.05) at 5 wk after weaning than at 2 wk after weaning. Eosinophils (P = 0.06) in the leukocyte population tended to be greater at 5 wk after weaning. Concentration of neutrophils in the leukocyte population and percentages of CD4 and CD8 cells were lower (P < 0.02) at 5 wk after weaning. The CD4:CD8 ratio (P = 0.07) tended to be lower at 5 wk after weaning. Results suggest that yeast culture could be an alternative to AGP in the diets of weanling pigs and that addition of CWP to diets containing YC would not improve the performance or health of weanling pigs above that of YC alone. Thus, more insight into the mode of action of YC is needed.

Effects of crystalline amino acid supplementation to the diet on odor from pig manure.

The objective of this study was to determine the effects of specific crystalline AA supplementation to a diet on odor emission, odor intensity, odor hedonic tone, and ammonia emission from pig manure, and on manure characteristics (pH; ammonia N; total nitrogen; sulfurous, indolic, and phenolic compounds; and VFA concentrations). An experiment was conducted with growing pigs (n = 18) in a randomized complete block design, with 3 treatments in 6 blocks. Treatment groups were (1) a 15%-CP basal diet with 3 times the requirement of sulfur-containing AA (14.2 g/kg of diet, as-fed basis); (2) the basal diet with 2 times the requirement of Trp and Phe+Tyr (2.9 and 20.4 g/kg of diet, respectively, as-fed basis); and (3) the basal diet with AA supplementation to levels sufficient for maximum protein gain. Pigs with an initial BW of 41.2 +/- 0.8 kg were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 times the maintenance requirement for NE (293 kJ/kg of BW(0.75)). Feed was mixed with water at 1:2.5 (wt/wt). Feces and urine of each pig was allowed to accumulate in separate manure pits under the slatted floor. After an adaptation period of 2 wk, and after cleaning the manure pits, manure was subsequently collected. In wk 5 of the collection period, separate samples were collected directly from each manure pit for odor, ammonia, and manure composition analyses. Air samples were analyzed for odor concentration and for hedonic tone and odor intensity above the odor detection threshold. Results showed that supplementing crystalline S-containing AA in surplus of the requirement increased odor emission (P < 0.001) and odor intensity (P < 0.05) and reduced odor hedonic tone (P < 0.05) from the air above the manure pits. Supplementing crystalline Trp, Tyr, and Phe in surplus of the recommended requirements did not affect odor emission, odor intensity, or odor hedonic tone. Regardless of dietary treatment, all pigs had similar performance levels. No differences were observed in ammonia emission from manure of pigs fed different levels of AA supplementation (P = 0.20). To reduce odor from pig manure, dietary S-containing AA should be minimized to just meet the recommended requirements.

Effects of additional starch or fat in late-gestating high nonstarch polysaccharide diets on litter performance and glucose tolerance in sows.

The effects of feeding additional starch or fat from d 85 of gestation until parturition on litter performance and on glucose tolerance in sows that were fed a diet with a high level of fermentable nonstarch polysaccharides (NSP) were studied. The day after breeding, 141 multiparous sows were assigned to the experiment. At d 85 of gestation, sows were assigned to the treatments. Sows were fed 3.4 kg/d (as-fed basis) of a high-NSP diet or the same quantity of the high-NSP diet and an additional 360 g of starch (from wheat starch) daily, or the same quantity of the high-NSP diet and an additional 164 g of fat (from soybean oil) daily. During lactation, all sows were given free access to the same lactation diet. Approximately 1 wk before the expected time of parturition, an oral glucose tolerance test was performed in 38 randomly chosen sows by feeding pelleted glucose (3 g/kg BW0.75). Blood samples for glucose analyses were taken at -10, 10, 20, 30, 40, 50, 60, 70, 80, 90, 105, and 120 min after glucose was fed. The supply of additional dietary starch or fat did not increase piglet birth weight or total litter weight at birth. Sows that were fed the high-NSP diet had more (P = 0.097) live-born piglets and fewer (P = 0.084) stillborn piglets than did sows that were fed additional fat, whereas sows that were fed additional starch were intermediate for these variables. Piglet mortality after birth was not affected by dietary treatment. Body weight and backfat gains in the last month of gestation were higher for sows fed additional starch or fat than for sows fed the high-NSP diet (P < 0.001 and P = 0.017, respectively). Feed intake in lactation was greatest by sows fed the high-NSP diet, least by sows fed additional starch at the end of gestation, and intermediate by sows fed additional fat (P = 0.099). The differences in lactation feed intake did not result in differences in BW and backfat losses during lactation. Sows that were fed additional fat had the greatest glucose area under the curve (P = 0.044), indicating that these sows were less tolerant to glucose. In conclusion, feeding additional energy (starch or fat) in late-gestating sows that are fed a high-NSP diet did not increase litter weight at birth or piglet survival, but did increase maternal gain. Feeding sows additional energy from fat might induce glucose intolerance, whereas feeding sows additional energy from starch did not induce glucose intolerance.

Performance and individual feed intake characteristics of group-housed sows fed a nonstarch polysaccharides diet ad libitum during gestation over three parities.

The objective of this experiment was to study the effects of feeding group-housed gestating sows a diet with a high level of fermentable nonstarch polysaccharides (NSP; approximately 45% sugar beet pulp as fed) ad libitum on the development in individual feed intake characteristics and reproductive performance during three successive reproduction cycles. Performance of the ad libitum-fed sows was compared to the performance of sows that were fed a conventional diet restrictedly. Feed intake characteristics during gestation were only measured in the ad libitum-fed sows. One hundred and nineteen sows were assigned to one of two gestation feeding regimens. Gestating sows were fed a conventional Dutch diet restrictedly or a diet with a high level of fermentable NSP ad libitum. During lactation, sows were given free access to a commercial lactation diet from d 6 after parturition onward. The ad libitum-fed sows ate 1.3 kg/d more during gestation than the restrictedly fed sows (P < 0.001), resulting in higher body weight and backfat gains during gestation (P < 0.05). Sows that were fed ad libitum during gestation lost more body weight and backfat during lactation (P < 0.001) than sows that were fed restrictedly during gestation. Feed intake during lactation, however, did not differ between sows that were fed restrictedly or ad libitum during gestation. The numbers of total piglets born, live-born and stillborn piglets, piglet birth weight, weaning-to-estrus interval, and percentage of sows that returned to estrus after first insemination were not affected by gestation feeding regimen. Mean daily voluntary feed intake (as-fed basis) over the three reproduction cycles in the ad libitum-fed gestating sows was 4.2 kg/d. Depending on the number of preceding reproduction cycles during which a sow was fed ad libitum, the maximum voluntary feed intake was reached in Parity 3, 4, or 5 and then remained stable in subsequent parities. Mean daily feed intake of the ad libitum-fed sows increased from wk 2 to 6 of gestation and then decreased to wk 15 of gestation. The mean number of daily visits with feed intake over the three reproduction cycles was 13.8. On average, ad libitum-fed sows spent 90 min/d on eating. This study shows that it is possible to feed gestating sows a diet with a high level of fermentable NSP ad libitum during three successive reproduction cycles without negative effects on reproductive performance.

Performance of sows fed high levels of nonstarch polysaccharides during gestation and lactation over three parities.

The effect of feeding sows a starch diet or a diet with a high level of nonstarch polysaccharides (NSP) during gestation, lactation, or both gestation and lactation during the first three parities on reproductive performance, body weight, and backfat was studied. Four-hundred and forty-four postpuberal gilts were allotted to a 2 x 2 x 2 factorial experiment. Treatments were diet composition during gestation (including the weaning-to-estrus interval; G-Starch: 274 g/kg of starch and 123 g/kg of fermentable NSP or G-NSP: 86 g/kg of starch and 300 g/kg of fermentable NSP), diet composition during lactation (L-Starch: 293 g/kg of starch and 113 g/kg of fermentable NSP or L-NSP: 189 g/kg of starch and 216 g/kg of fermentable NSP) and group-housing system during gestation (free access stalls or electronic feeding). Both gestation diets were formulated to be isoenergetic. During lactation, sows were given free access to the lactation diets from d 6 after parturition onwards. Body weight and backfat gains during gestation were lower in sows fed the G-NSP diet than in those fed the G-starch diet (P < 0.001). The effects were more pronounced in the electronic feeding system than in the free access stalls. These results indicate an overestimation of the energy value of fermentable NSP. Body weight and backfat losses during lactation were less in sows fed the G-NSP diet during gestation than in those fed the G-starch diet (P < 0.05),which can be explained by a 0.4 kg/d higher (P < 0.001) feed intake during lactation of the sows fed the G-NSP diet. Sows fed the L-NSP diet lost more backfat during lactation than sows fed the L-starch diet (P < 0.05). The number of total piglets born and live-born piglets was 0.5 piglet higher in sows fed the G-NSP diet than in those fed the G-starch diet (P < 0.05). Lactation diet did not affect the number of total piglets born or live-born piglets. This study shows that, although high NSP diets negatively influence body weight and backfat thickness of the sows, it is possible to feed sows a diet with a high level of fermentable NSP diet during both gestation and lactation without negative effects on reproductive performance. Under the conditions of this study, feeding sows a diet with a high level of fermentable NSP during gestation and a high level of starch during lactation seems the most favorable feeding strategy.

A prolonged photoperiod improves feed intake and energy metabolism of weanling pigs.

In a 2-wk experiment, the effect of photoperiod on performance and energy metabolism of newly weaned pigs was studied. Forty 4-wk-old crossbred weanling barrows weighing 8.0 kg (SE = 0.13) were assigned to one of eight groups (five pigs per group) based on BW and litter. Groups were allotted to one of two lighting schedules: 8 h light:16 h darkness or 23 h light:1 h darkness. Each group was housed in a climate respiration chamber. Piglets had ad libitum access to feed and water. Energy and nitrogen balances, heat production, ADFI, and ADG were measured weekly. Heat production, energy metabolism, and performance were unaffected (P > 0.10) by photoperiod during wk 1. However, in the 2nd wk ADFI (418 vs 302 g/d) and ADG (381 vs 240 g/d) were higher (P < 0.05 and P = 0.05, respectively) for pigs on the 23:1 h lighting schedule than for those on the 8:16 h schedule. Furthermore, heat production (P < 0.10), total energy retention, and energy retained as protein and as fat were higher (P < 0.05) during wk 2 in pigs on the 23:1 h lighting schedule (8, 125, 41, and 350%, respectively) than in those on the 8:16 h schedule. Moreover, metabolizability of energy tended to be higher (P < 0.10) and energy requirements for maintenance were lower (P < 0.05) during wk 2 for pigs on the 23:1 h schedule compared with those on the 8:16 h schedule (P < 0.10). In conclusion, exposing pigs to a longer period of light after weaning stimulated ADFI and ADG. In addition to the feed intake, the high ADG is due to an improved metabolizability of energy and a reduced energy requirement for maintenance. This study suggests that lighting schedule can be used as a tool to stimulate feed intake after weaning.