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Intermittent suckling improves post-weaning feed uptake but does not change functional gut characteristics of piglets
Livestock Science 108 (2007) 132 – 136 www.elsevier.com/locate/livsci
Intermittent suckling improves post-weaning feed uptake but does not change functional gut characteristics of piglets ☆ T. Thymann a,⁎, C. Gudbergsen a , S. Bresson a , N.B. Kristensen b , C.F. Hansen c a
University of Copenhagen, Faculty of Life Sciences, Department of Human Nutrition / Department of Large Animal Sciences, Frederiksberg, Denmark b University of Aarhus, Faculty of Agricultural Sciences, Department of Physiology and Nutrition, Foulum, Denmark c Danish Pig Production, Department of Nutrition, Copenhagen, Denmark
Abstract Suckling pigs were separated from their dam for 24 h on day 21 (1 × 24 h fasting, n = 10) or day 21 and 24 (2 × 24 h fasting, n = 10). Pigs in the control group (n = 10) were not fasted before weaning. All pigs were weaned on day 28 postpartum. Feed intake during the first 4 days post-weaning was higher (P b 0.05) for pigs exposed to 1 × 24 h fasting compared with controls. Water consumption was not affected by fasting prior to weaning. The difference in post-weaning feed uptake was not reflected in any clinical traits, intestinal morphology, or activity of digestive enzymes (maltase, dipeptidylpeptidase IV, aminopeptidases A and N; P N 0.15). In conclusion, a short period of fasting prior to weaning can increase post-weaning feed uptake, although this had no clinical impact under the present experimental conditions. © 2007 Elsevier B.V. All rights reserved. Keywords: Weaning; Lactation; Intestine; Feed uptake
1. Introduction Development of gut malfunction and diarrhea in the early post-weaning period, remains a major clinical problem in swine production. Low feed intake in the days immediately after weaning is closely related to gastrointestinal atrophy, malfunction and disease sus-
☆ This paper is part of the special issue entitled “Digestive Physiology in Pigs” guest edited by José Adalberto Fernández, Mette Skou Hedemann, Bent Borg Jensen, Henry Jørgensen, Knud Erik Bach Knudsen and Helle Nygaard Lærke. ⁎ Corresponding author. University of Copenhagen, Faculty of Life Sciences, Department of Human Nutrition, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark. Tel.: +45 35282622; fax: +45 35282483. E-mail address: [email protected] (T. Thymann).
1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.01.023
ceptibility (Kelly et al., 1991; Pluske et al., 1996; van Beers-Schreurs et al., 1998; Madec et al., 1998). We hypothesized that the weaning transition is a process in which some key intestinal morphological, hormonal, digestive and microbiological adaptations naturally occur and that this adaptation is partly triggered by the post-weaning fasting condition. Data from Kuller et al. (2004) show that short fasting periods prior to weaning has a stimulating effect on post-weaning feed intake although body weight at weaning is reduced. Yet Chapple et al. (1989) found that low-body weight litter mates were more developed in their digestive system than high-body weight litter mates. We therefore hypothesized that some of these essential adaptations could be induced already before weaning by exposing suckling pigs to a short period of fasting that may both
T. Thymann et al. / Livestock Science 108 (2007) 132–136
stimulate post-weaning feed uptake and mature the digestive system in general. The objective of this study was therefore to subject suckling pigs to a short period of fasting, followed by post-weaning observations on feed and water uptake, growth performance and gut function and morphology. 2. Materials and methods 2.1. Treatments On day 21 postpartum we separated ten suckling pigs from their mothers (Landrace × Yorkshire) for 24 h (1 × 24 h fasting, n = 10). Another ten pigs were separated from their mothers for 24 h on day 21 and 24 postpartum (2 × 24 h fasting, n = 10). The fasted pigs were obtained randomly from four different sows. During separation the pigs had ad libitum access to water. No solid food was offered during the separation periods or during the suckling period. Pigs not subjected to fasting during the lactation period served as controls (control, n = 10). After separation all pigs were allowed to nurse until day 28 postpartum, then weaned and kept individually in separate pens for seven days. All weaned pigs had ad libitum access to water and dry feed. Daily registrations included individual feed consumption, body weight and fecal consistency score (1: firm well formed, 2: soft, 3: loose, 4: watery). Further, pigs were injected i.m. at the time of weaning with 0.5 g/kg bodyweight of a 20% solution of deuterium oxide (D2O) to measure whole body water turnover. To study the subsequent dilution of plasma deuterium from consumption of water, we collected blood samples from the jugular vein prior to injection (baseline), one hour post injection (equilibration) and daily for the following seven days post-weaning. 2.2. Tissue collection Seven days post-weaning, all pigs were anaesthetized with Zoletil 50 (zolazepam/tiletamin, Boehringer Ingelheim, Copenhagen, Denmark) and subsequently euthanized with an intra-cardiac injection of sodium pentobarbitone. Immediately after euthanization, the intestine was excised and sections at 80 cm caudal to the pyloric sphinter (proximal), 80 cm cranial to the ileocecal valve (distal), and the middle colon respectively, were excised and snap frozen in liquid nitrogen and stored at − 80 °C for analysis of digestive enzyme activity. A second set of tissue samples from the distal small intestine were fixed in paraformaldehyde for 24 h and subsequently dehydrated and stored in 70% ethanol.
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Finally, weights of the heart, lungs, liver, kidneys, adrenals, spleen, pancreas, stomach, small intestine and colon were recorded. 2.3. Enzyme activity Activities of maltase–glucoamylase (EC 3.2.1.20), dipeptidyl–peptidase IV (EC 3.4.14.5), aminopeptidase N (EC 3.4.11.2) and aminopeptidase A (EC 3.4.11.7) in homogenates of proximal and distal small intestinal tissue were determined spectrofotometrically at 405 nm using maltose, glycyl-L-prolin-4-nitroanilide, L-alanine-4-nitroanilide, and α-L-glutamic acid 4-nitroanilide as substrates respectively, according to a previously established protocol (Sangild et al., 1995). For all enzymes, a hydrolytic rate of 1 μmol substrate released/ min at 37 °C was considered to represent 1 U of enzyme activity. Enzyme activities were expressed per gram of wet intestine. 2.4. Histology Dehydrated tissue samples from the distal small intestine were infiltrated with paraffin and cut in slices of 3 μm and stained with periodic acid-Schiff (PAS) reaction. Villous height, villous width and crypt depth were measured on 15 well oriented villi and crypts in each sample, using a light microscope (Orthoplane, Leitz, Germany) and NIH Image J software (version 1.22c, National Institutes of Health, Bethesda, MD). 2.5. Deuterium oxide The deuterium abundance in plasma water was determined by isotope ratio mass spectrometry on hydrogen liberated by reaction of plasma water with chromium at 900 °C as previously described (Theil et al., 2002). Plasma was deproteinized by ultrafiltration (VectaSpin Micro 20 K MWCO, Whatman plc., Brentford, UK). 2.6. Statistics The effects of treatments on body and organ weights, morphology and enzyme activity were evaluated by the MIXED procedure of the SAS software package version 8.2 (SAS Institute, Cary, NC, USA) using treatment and intestinal region as fixed variables and sow and pig as random variables. Differences between individual treatment means (presented as raw means ± se) were tested using the PDIFF option of SAS. Data on water and feed uptake, fecal score, and daily weight gain were analyzed
134
T. Thymann et al. / Livestock Science 108 (2007) 132–136
as repeated measures using a Gaussian model of spatial correlation in the MIXED procedure of SAS. Probability levels below 0.05 were considered significant.
Fig. 1. Daily post-weaning registrations of feed uptake (g/d), fecal consistency score (1: firm well formed, 2: soft, 3: loose, 4: watery), weight gain (g/d) and water consumption (g/d). Indication of different letters to the right of each graph, represent significant difference as estimated in a repeated measure analysis. Each time point represents means ± std. err., (n = 10 for all groups).
Fig. 2. Villus height and crypt depth (μm) in the distal small intestine (upper panel). Activity of gut digestive enzymes (Aminopeptidase A and N, Dipeptidylpeptidase IV and Maltase; U/g tissue). Data on enzyme activity are pooled across intestinal region (proximal and distal small intestine). Bars and crossbars represent means ± std. err. (n = 10 for all groups).
T. Thymann et al. / Livestock Science 108 (2007) 132–136
3. Results During the 24 h of feed deprivation piglets subjected to fasting had an average body weight loss of 220 ± 45 g whereas pigs in the control group had a bodyweight gain of 350 ± 73 g during the same 24 h period. As a consequence the bodyweight at weaning tended to be lower in the 2 × 24 h fasting group compared with controls (7.64 ± 0.40 kg vs 8.07 ± 0.46 kg, P = 0.08) whereas 1 × 24 h fasting did not affect bodyweight at weaning compared with control (8.00 ± 0.53 kg, P N 0.15). Feed uptake during the first 24 h was equally low for all groups (approx. 50 g per pig, Fig. 1), yet during the following 3 days feed intake was higher in the 1 × 24 h fasting group compared with controls (P b 0.05). Higher feed intake was reflected in higher body weight gain during days 2 and 3 for the 1 × 24 h fasting group compared with controls, whereas the 2 × 24 h group was intermediate in body weight gain and not significantly different from the other groups (Fig. 1). Daily water consumption varied largely between pigs, and there was no detectable difference between treatment groups (Fig. 1). Interestingly however, water consumption seemed to follow a certain longitudinal pattern regardless of treatment (Fig. 1). From day three to four post weaning water uptake decreased and fecal score increased (more liquid), but from day four to five both water consumption and fecal score increased. Fecal score followed the same pattern for all groups and was not significantly different between the groups (Fig. 1). A maximum of approx. 1.5 in fecal score was reached on day five post-weaning which corresponded to relatively soft stools, but not clinical diarrhea. Weights of organs (heart, lungs, liver, spleen, adrenals, kidneys, small intestine, ventricle, and colon) relative to body weight, were similar between treatment groups (P N 0.15, data not shown). Likewise, neither the activity of intestinal brush border enzymes nor morphological measurements showed any effect of treatment (Fig. 2). Data for enzyme activity are pooled across intestinal region whereas morphological measurements represent the distal small intestine only. 4. Discussion Numerous studies have focused on improving postweaning diets, however the potential beneficial effects of feed additives requires that the newly weaned pigs eat acceptable amounts of dry feed. The link between feed uptake and disease susceptibility in the weeks postweaning (Kelly et al., 1991; Pluske et al., 1996; van Beers-Schreurs et al., 1998) has led research groups to
135
study different aspects of eating behaviour and feed intake and composition. It has been shown that there is large variation in the latency time before the first meal after weaning (Bruininx et al., 2001) and it appears that feed intake per se, rather than feed composition, is the important factor for optimal gastrointestinal maturation and health immediately after weaning (van BeersSchreurs et al., 1998). Although pigs that eat sufficient feed immediately after weaning have larger intestinal villi and brush-border enzyme activities, a large proportion of these pigs also have diarrhea (Spreeuwenberg et al., 2002). In addition research has shown that intake of significant amounts of dry feed before weaning does not prevent weaning diarrhea (Kelly et al., 1990). On the one hand we found that a short period of fasting prior to weaning stimulates post-weaning feed uptake, but on the other hand higher feed uptake had no beneficial effects on gut functional parameters like morphology and enzyme activity. To allow measurement of individual feed uptake we housed the pigs in separate pens characterized by highly sanitary conditions and a low infectious level. As a result all pigs remained clinically healthy although fecal score increased slightly. The lack of sensitivity to weaninginduced diarrhea may have biased the responses to treatment. It therefore seems necessary to study the potential beneficial effect of a short pre-weaning fasting period in a more sensitive system. This could likely be achieved using group housing and slightly poorer sanitary conditions. Our data suggest that the weaning transition is a fundamental biological process that cannot be circumvented alone by an increased intake of dry feed after weaning. The absence of antimicrobials in feed places an increased demand on the endogenous adaptive response to weaning. We therefore need to explore more of the animal factors that enable some pigs to adapt quickly to a weaning transition and make them less sensitive to weaning diarrhea, even in group housing conditions. References Bruininx, E.M., van der Peet-Schwering, C.M., Schrama, J.W., Vereijken, P.F., Vesseur, P.C., Everts, H., den Hartog, L.A., Beynen, A.C., 2001. Individually measured feed intake characteristics and growth performance of group-housed weanling pigs: effects of sex, initial body weight, and body weight distribution within groups. J. Anim. Sci. 79, 301–308. Chapple, R.P., Cuaron, J.A., Easter, R.A., 1989. Effect of glucocorticoids and limiting nursing on the carbohydrate digestive capacity and growth rate of piglets. J. Anim. Sci. 67 (11), 2956–2973, Nov. Kelly, D., O'Brien, J.J., McCracken, K.J., 1990. Effect of creep feeding on the incidence, duration and severity of post-weaning diarrhoea in pigs. Res. Vet. Sci. 49, 223–228.
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Kelly, D., Smyth, J.A., McCracken, K.J., 1991. Digestive development of the early-weaned pig. 1. Effect of continuous nutrient supply on the development of the digestive tract and on changes in digestive enzyme activity during the first week post-weaning. Br. J. Nutr. 65, 169–180. Kuller, W.I., Soede, N.M., Van Beeers-Schreurs, H.M.G., Langendijk, P., Taverne, M.A.M., Verheijden, J.H.M., Kemp, B., 2004. Intermittent suckling: effects on piglet and sow performance before and after weaning. J. Anim. Sci. 82, 405–413. Madec, F., Bridoux, N., Bounaix, S., Jestin, A., 1998. Measurement of digestive disorders in the piglet at weaning and related risk factors. Prev. Vet. Med. 35, 53–72. Pluske, J.R., Williams, I.H., Aherne, F.X., 1996. Villous height and crypt depth in piglets in response to increases in the intake of cows’ milk after weaning. Anim. Sci. 62, 145–158. Sangild, P.T., Sjostrom, H., Noren, O., Fowden, A.L., Silver, M., 1995. The prenatal development and glucocorticoid weaned control of brush-border hydrolases in the pig small intestine. Pediatr. Res. 37, 207–212.
Spreeuwenberg, M.A.M., Verdonk, J.M.A.J., Beynen, A.C., Verstegen, M.W.A., 2002. Interrelationship between gut morphology and faeces consistency in newly weaned piglets. Ph.D. thesis: Diet composition and gut integrity in weaned piglets. Wageningen University. Theil, P.K., Nielsen, T.T., Kristensen, N.B., Labouriau, R., Danielsen, V., Lauridsen, C., Jakobsen, K., 2002. Estimation of milk production in lactating sows by determination of deuterated water turnover in three piglets per litter. Acta Agric. Scand. Sect. A 52, 221–232. van Beers-Schreurs, H.M., Nabuurs, M.J., Vellenga, L., Kalsbeek-van der Valk, H.J., Wensing, T., Breukink, H.J., 1998. Weaning and the weanling diet influence the villous height and crypt depth in the small intestine of pigs and alter the concentrations of short-chain fatty acids in the large intestine and blood. J. Nutr. 128, 947–953.
Intermittent suckling improves post-weaning feed uptake but does not change functional gut characteristics of piglets ☆ T. Thymann a,⁎, C. Gudbergsen a , S. Bresson a , N.B. Kristensen b , C.F. Hansen c a
University of Copenhagen, Faculty of Life Sciences, Department of Human Nutrition / Department of Large Animal Sciences, Frederiksberg, Denmark b University of Aarhus, Faculty of Agricultural Sciences, Department of Physiology and Nutrition, Foulum, Denmark c Danish Pig Production, Department of Nutrition, Copenhagen, Denmark
Abstract Suckling pigs were separated from their dam for 24 h on day 21 (1 × 24 h fasting, n = 10) or day 21 and 24 (2 × 24 h fasting, n = 10). Pigs in the control group (n = 10) were not fasted before weaning. All pigs were weaned on day 28 postpartum. Feed intake during the first 4 days post-weaning was higher (P b 0.05) for pigs exposed to 1 × 24 h fasting compared with controls. Water consumption was not affected by fasting prior to weaning. The difference in post-weaning feed uptake was not reflected in any clinical traits, intestinal morphology, or activity of digestive enzymes (maltase, dipeptidylpeptidase IV, aminopeptidases A and N; P N 0.15). In conclusion, a short period of fasting prior to weaning can increase post-weaning feed uptake, although this had no clinical impact under the present experimental conditions. © 2007 Elsevier B.V. All rights reserved. Keywords: Weaning; Lactation; Intestine; Feed uptake
1. Introduction Development of gut malfunction and diarrhea in the early post-weaning period, remains a major clinical problem in swine production. Low feed intake in the days immediately after weaning is closely related to gastrointestinal atrophy, malfunction and disease sus-
☆ This paper is part of the special issue entitled “Digestive Physiology in Pigs” guest edited by José Adalberto Fernández, Mette Skou Hedemann, Bent Borg Jensen, Henry Jørgensen, Knud Erik Bach Knudsen and Helle Nygaard Lærke. ⁎ Corresponding author. University of Copenhagen, Faculty of Life Sciences, Department of Human Nutrition, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark. Tel.: +45 35282622; fax: +45 35282483. E-mail address: [email protected] (T. Thymann).
1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.01.023
ceptibility (Kelly et al., 1991; Pluske et al., 1996; van Beers-Schreurs et al., 1998; Madec et al., 1998). We hypothesized that the weaning transition is a process in which some key intestinal morphological, hormonal, digestive and microbiological adaptations naturally occur and that this adaptation is partly triggered by the post-weaning fasting condition. Data from Kuller et al. (2004) show that short fasting periods prior to weaning has a stimulating effect on post-weaning feed intake although body weight at weaning is reduced. Yet Chapple et al. (1989) found that low-body weight litter mates were more developed in their digestive system than high-body weight litter mates. We therefore hypothesized that some of these essential adaptations could be induced already before weaning by exposing suckling pigs to a short period of fasting that may both
T. Thymann et al. / Livestock Science 108 (2007) 132–136
stimulate post-weaning feed uptake and mature the digestive system in general. The objective of this study was therefore to subject suckling pigs to a short period of fasting, followed by post-weaning observations on feed and water uptake, growth performance and gut function and morphology. 2. Materials and methods 2.1. Treatments On day 21 postpartum we separated ten suckling pigs from their mothers (Landrace × Yorkshire) for 24 h (1 × 24 h fasting, n = 10). Another ten pigs were separated from their mothers for 24 h on day 21 and 24 postpartum (2 × 24 h fasting, n = 10). The fasted pigs were obtained randomly from four different sows. During separation the pigs had ad libitum access to water. No solid food was offered during the separation periods or during the suckling period. Pigs not subjected to fasting during the lactation period served as controls (control, n = 10). After separation all pigs were allowed to nurse until day 28 postpartum, then weaned and kept individually in separate pens for seven days. All weaned pigs had ad libitum access to water and dry feed. Daily registrations included individual feed consumption, body weight and fecal consistency score (1: firm well formed, 2: soft, 3: loose, 4: watery). Further, pigs were injected i.m. at the time of weaning with 0.5 g/kg bodyweight of a 20% solution of deuterium oxide (D2O) to measure whole body water turnover. To study the subsequent dilution of plasma deuterium from consumption of water, we collected blood samples from the jugular vein prior to injection (baseline), one hour post injection (equilibration) and daily for the following seven days post-weaning. 2.2. Tissue collection Seven days post-weaning, all pigs were anaesthetized with Zoletil 50 (zolazepam/tiletamin, Boehringer Ingelheim, Copenhagen, Denmark) and subsequently euthanized with an intra-cardiac injection of sodium pentobarbitone. Immediately after euthanization, the intestine was excised and sections at 80 cm caudal to the pyloric sphinter (proximal), 80 cm cranial to the ileocecal valve (distal), and the middle colon respectively, were excised and snap frozen in liquid nitrogen and stored at − 80 °C for analysis of digestive enzyme activity. A second set of tissue samples from the distal small intestine were fixed in paraformaldehyde for 24 h and subsequently dehydrated and stored in 70% ethanol.
133
Finally, weights of the heart, lungs, liver, kidneys, adrenals, spleen, pancreas, stomach, small intestine and colon were recorded. 2.3. Enzyme activity Activities of maltase–glucoamylase (EC 3.2.1.20), dipeptidyl–peptidase IV (EC 3.4.14.5), aminopeptidase N (EC 3.4.11.2) and aminopeptidase A (EC 3.4.11.7) in homogenates of proximal and distal small intestinal tissue were determined spectrofotometrically at 405 nm using maltose, glycyl-L-prolin-4-nitroanilide, L-alanine-4-nitroanilide, and α-L-glutamic acid 4-nitroanilide as substrates respectively, according to a previously established protocol (Sangild et al., 1995). For all enzymes, a hydrolytic rate of 1 μmol substrate released/ min at 37 °C was considered to represent 1 U of enzyme activity. Enzyme activities were expressed per gram of wet intestine. 2.4. Histology Dehydrated tissue samples from the distal small intestine were infiltrated with paraffin and cut in slices of 3 μm and stained with periodic acid-Schiff (PAS) reaction. Villous height, villous width and crypt depth were measured on 15 well oriented villi and crypts in each sample, using a light microscope (Orthoplane, Leitz, Germany) and NIH Image J software (version 1.22c, National Institutes of Health, Bethesda, MD). 2.5. Deuterium oxide The deuterium abundance in plasma water was determined by isotope ratio mass spectrometry on hydrogen liberated by reaction of plasma water with chromium at 900 °C as previously described (Theil et al., 2002). Plasma was deproteinized by ultrafiltration (VectaSpin Micro 20 K MWCO, Whatman plc., Brentford, UK). 2.6. Statistics The effects of treatments on body and organ weights, morphology and enzyme activity were evaluated by the MIXED procedure of the SAS software package version 8.2 (SAS Institute, Cary, NC, USA) using treatment and intestinal region as fixed variables and sow and pig as random variables. Differences between individual treatment means (presented as raw means ± se) were tested using the PDIFF option of SAS. Data on water and feed uptake, fecal score, and daily weight gain were analyzed
134
T. Thymann et al. / Livestock Science 108 (2007) 132–136
as repeated measures using a Gaussian model of spatial correlation in the MIXED procedure of SAS. Probability levels below 0.05 were considered significant.
Fig. 1. Daily post-weaning registrations of feed uptake (g/d), fecal consistency score (1: firm well formed, 2: soft, 3: loose, 4: watery), weight gain (g/d) and water consumption (g/d). Indication of different letters to the right of each graph, represent significant difference as estimated in a repeated measure analysis. Each time point represents means ± std. err., (n = 10 for all groups).
Fig. 2. Villus height and crypt depth (μm) in the distal small intestine (upper panel). Activity of gut digestive enzymes (Aminopeptidase A and N, Dipeptidylpeptidase IV and Maltase; U/g tissue). Data on enzyme activity are pooled across intestinal region (proximal and distal small intestine). Bars and crossbars represent means ± std. err. (n = 10 for all groups).
T. Thymann et al. / Livestock Science 108 (2007) 132–136
3. Results During the 24 h of feed deprivation piglets subjected to fasting had an average body weight loss of 220 ± 45 g whereas pigs in the control group had a bodyweight gain of 350 ± 73 g during the same 24 h period. As a consequence the bodyweight at weaning tended to be lower in the 2 × 24 h fasting group compared with controls (7.64 ± 0.40 kg vs 8.07 ± 0.46 kg, P = 0.08) whereas 1 × 24 h fasting did not affect bodyweight at weaning compared with control (8.00 ± 0.53 kg, P N 0.15). Feed uptake during the first 24 h was equally low for all groups (approx. 50 g per pig, Fig. 1), yet during the following 3 days feed intake was higher in the 1 × 24 h fasting group compared with controls (P b 0.05). Higher feed intake was reflected in higher body weight gain during days 2 and 3 for the 1 × 24 h fasting group compared with controls, whereas the 2 × 24 h group was intermediate in body weight gain and not significantly different from the other groups (Fig. 1). Daily water consumption varied largely between pigs, and there was no detectable difference between treatment groups (Fig. 1). Interestingly however, water consumption seemed to follow a certain longitudinal pattern regardless of treatment (Fig. 1). From day three to four post weaning water uptake decreased and fecal score increased (more liquid), but from day four to five both water consumption and fecal score increased. Fecal score followed the same pattern for all groups and was not significantly different between the groups (Fig. 1). A maximum of approx. 1.5 in fecal score was reached on day five post-weaning which corresponded to relatively soft stools, but not clinical diarrhea. Weights of organs (heart, lungs, liver, spleen, adrenals, kidneys, small intestine, ventricle, and colon) relative to body weight, were similar between treatment groups (P N 0.15, data not shown). Likewise, neither the activity of intestinal brush border enzymes nor morphological measurements showed any effect of treatment (Fig. 2). Data for enzyme activity are pooled across intestinal region whereas morphological measurements represent the distal small intestine only. 4. Discussion Numerous studies have focused on improving postweaning diets, however the potential beneficial effects of feed additives requires that the newly weaned pigs eat acceptable amounts of dry feed. The link between feed uptake and disease susceptibility in the weeks postweaning (Kelly et al., 1991; Pluske et al., 1996; van Beers-Schreurs et al., 1998) has led research groups to
135
study different aspects of eating behaviour and feed intake and composition. It has been shown that there is large variation in the latency time before the first meal after weaning (Bruininx et al., 2001) and it appears that feed intake per se, rather than feed composition, is the important factor for optimal gastrointestinal maturation and health immediately after weaning (van BeersSchreurs et al., 1998). Although pigs that eat sufficient feed immediately after weaning have larger intestinal villi and brush-border enzyme activities, a large proportion of these pigs also have diarrhea (Spreeuwenberg et al., 2002). In addition research has shown that intake of significant amounts of dry feed before weaning does not prevent weaning diarrhea (Kelly et al., 1990). On the one hand we found that a short period of fasting prior to weaning stimulates post-weaning feed uptake, but on the other hand higher feed uptake had no beneficial effects on gut functional parameters like morphology and enzyme activity. To allow measurement of individual feed uptake we housed the pigs in separate pens characterized by highly sanitary conditions and a low infectious level. As a result all pigs remained clinically healthy although fecal score increased slightly. The lack of sensitivity to weaninginduced diarrhea may have biased the responses to treatment. It therefore seems necessary to study the potential beneficial effect of a short pre-weaning fasting period in a more sensitive system. This could likely be achieved using group housing and slightly poorer sanitary conditions. Our data suggest that the weaning transition is a fundamental biological process that cannot be circumvented alone by an increased intake of dry feed after weaning. The absence of antimicrobials in feed places an increased demand on the endogenous adaptive response to weaning. We therefore need to explore more of the animal factors that enable some pigs to adapt quickly to a weaning transition and make them less sensitive to weaning diarrhea, even in group housing conditions. References Bruininx, E.M., van der Peet-Schwering, C.M., Schrama, J.W., Vereijken, P.F., Vesseur, P.C., Everts, H., den Hartog, L.A., Beynen, A.C., 2001. Individually measured feed intake characteristics and growth performance of group-housed weanling pigs: effects of sex, initial body weight, and body weight distribution within groups. J. Anim. Sci. 79, 301–308. Chapple, R.P., Cuaron, J.A., Easter, R.A., 1989. Effect of glucocorticoids and limiting nursing on the carbohydrate digestive capacity and growth rate of piglets. J. Anim. Sci. 67 (11), 2956–2973, Nov. Kelly, D., O'Brien, J.J., McCracken, K.J., 1990. Effect of creep feeding on the incidence, duration and severity of post-weaning diarrhoea in pigs. Res. Vet. Sci. 49, 223–228.
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Kelly, D., Smyth, J.A., McCracken, K.J., 1991. Digestive development of the early-weaned pig. 1. Effect of continuous nutrient supply on the development of the digestive tract and on changes in digestive enzyme activity during the first week post-weaning. Br. J. Nutr. 65, 169–180. Kuller, W.I., Soede, N.M., Van Beeers-Schreurs, H.M.G., Langendijk, P., Taverne, M.A.M., Verheijden, J.H.M., Kemp, B., 2004. Intermittent suckling: effects on piglet and sow performance before and after weaning. J. Anim. Sci. 82, 405–413. Madec, F., Bridoux, N., Bounaix, S., Jestin, A., 1998. Measurement of digestive disorders in the piglet at weaning and related risk factors. Prev. Vet. Med. 35, 53–72. Pluske, J.R., Williams, I.H., Aherne, F.X., 1996. Villous height and crypt depth in piglets in response to increases in the intake of cows’ milk after weaning. Anim. Sci. 62, 145–158. Sangild, P.T., Sjostrom, H., Noren, O., Fowden, A.L., Silver, M., 1995. The prenatal development and glucocorticoid weaned control of brush-border hydrolases in the pig small intestine. Pediatr. Res. 37, 207–212.
Spreeuwenberg, M.A.M., Verdonk, J.M.A.J., Beynen, A.C., Verstegen, M.W.A., 2002. Interrelationship between gut morphology and faeces consistency in newly weaned piglets. Ph.D. thesis: Diet composition and gut integrity in weaned piglets. Wageningen University. Theil, P.K., Nielsen, T.T., Kristensen, N.B., Labouriau, R., Danielsen, V., Lauridsen, C., Jakobsen, K., 2002. Estimation of milk production in lactating sows by determination of deuterated water turnover in three piglets per litter. Acta Agric. Scand. Sect. A 52, 221–232. van Beers-Schreurs, H.M., Nabuurs, M.J., Vellenga, L., Kalsbeek-van der Valk, H.J., Wensing, T., Breukink, H.J., 1998. Weaning and the weanling diet influence the villous height and crypt depth in the small intestine of pigs and alter the concentrations of short-chain fatty acids in the large intestine and blood. J. Nutr. 128, 947–953.