Zinc attenuates forskolin-stimulated electrolyte secretion without involvement of the enteric nervous system in small intestinal epithelium from weaned piglets

In a previous study, we found that secretagogue-stimulated electrolyte secretion was attenuated by dietary and serosal zinc in piglet small intestinal epithelium in Ussing chambers. Several studies show that the enteric nervous system (ENS) is involved in regulation of electrolyte and/or fluid transport in intestinal epithelium from many species. The aim of the present study is to examine the mechanisms behind the attenuating effect of zinc on electrolyte secretion and to study whether the ENS is involved in this effect of zinc in vitro. Twenty-four piglets (six litters of four piglets) were allocated randomly to one of two dietary treatments consisting of a basic diet supplemented with 100 mg zinc/kg (Zn(100)) or 2500 mg zinc/kg (Zn(2500)), as ZnO. All the piglets were killed at 5-6 days after weaning and in vitro experiments with small intestinal epithelium in Ussing chambers were carried out. Furthermore, zinc, copper, alkaline phosphatase (AP) and metallothionein (MT) in mucosa, liver, and plasma were measured. These measurements showed that zinc status was increased in the Zn(2500) compared to the Zn(100) fed piglets. The in vitro studies did not confirm previous findings of attenuating effects of dietary zinc and zinc in vitro on the 5-HT induced secretion. But it showed that the addition of zinc at the serosal side attenuated the forskolin (FSK) (cAMP-dependent) induced ion secretion in epithelium from piglets fed with Zn(100) diet. Blocking the ENS with lidocaine or hexamethonium apparently slightly reduced this effect of zinc in vitro, but did not remove the effect of zinc. Consequently, it is suggested that zinc attenuates the cAMP dependent ion secretion mainly due to an effect on epithelial cells rather than affecting the mucosal neuronal pathway.     

Serosal zinc attenuate serotonin and vasoactive intestinal peptide induced secretion in piglet small intestinal epithelium in vitro

This study addressed the mechanisms by which dietary zinc affects diarrhoea and aimed to study possible interactions between zinc status and the presence of zinc in vitro on secretagogue-induced secretion from piglet intestinal epithelium in Ussing chambers. In addition, it was studied from which side of the epithelium zinc would perform an effect and if copper caused similar effects. Twenty-four piglets (28 days of age) were weaned and fed diets containing 100 or 2500 mg zinc/kg (as ZnO) for 5 or 6 days (12 piglets per group). Intestinal epithelium underwent the following 5 treatments: zinc at the mucosal side (M(Zn)), zinc at the serosal side (S(Zn)), zinc at both sides (MS(Zn)), copper at both sides (MS(Cu)) or water at both sides (control). Provoked secretion in terms of short circuit responses to serotonin (5-HT) and vasoactive intestinal peptide (VIP) were measured. Zinc at the serosal or both sides of the epithelium reduced the 5-HT induced secretion (P<0.001); however, due to interactions (P=0.05) the effect of zinc in vitro was only present in the ZnO(100) group. The secretion caused by VIP was not affected by the diet (P=0.33), but zinc at the serosal side or both sides reduced the response to VIP (P<0.001). Copper reduced the 5-HT and VIP induced secretion to a larger extent than zinc. However, copper also disturbed intestinal barrier function as demonstrated by increased transepithelial conductance and increased short circuit current, which was unaffected by zinc. In conclusion, zinc at the serosal side of piglet small intestinal epithelium attenuated 5-HT and VIP induced secretion in vitro. These in vitro studies indicate that in vivo there will be no positive acute effect of increasing luminal Zn concentration on secretagogue-induced chloride secretion and that zinc status at the serosal side of the epithelium has to be increased to reduce secretagogue-induced chloride secretion and thereby diarrhoea.     

Serosal zinc attenuate serotonin and vasoactive intestinal peptide induced secretion in piglet small intestinal epithelium in vitro.

This study addressed the mechanisms by which dietary zinc affects diarrhoea and aimed to study possible interactions between zinc status and the presence of zinc in vitro on secretagogue-induced secretion from piglet intestinal epithelium in Ussing chambers. In addition, it was studied from which side of the epithelium zinc would perform an effect and if copper caused similar effects. Twenty-four piglets (28 days of age) were weaned and fed diets containing 100 or 2500 mg zinc/kg (as ZnO) for 5 or 6 days (12 piglets per group). Intestinal epithelium underwent the following 5 treatments: zinc at the mucosal side (M(Zn)), zinc at the serosal side (S(Zn)), zinc at both sides (MS(Zn)), copper at both sides (MS(Cu)) or water at both sides (control). Provoked secretion in terms of short circuit responses to serotonin (5-HT) and vasoactive intestinal peptide (VIP) were measured. Zinc at the serosal or both sides of the epithelium reduced the 5-HT induced secretion (P<0.001); however, due to interactions (P=0.05) the effect of zinc in vitro was only present in the ZnO(100) group. The secretion caused by VIP was not affected by the diet (P=0.33), but zinc at the serosal side or both sides reduced the response to VIP (P<0.001). Copper reduced the 5-HT and VIP induced secretion to a larger extent than zinc. However, copper also disturbed intestinal barrier function as demonstrated by increased transepithelial conductance and increased short circuit current, which was unaffected by zinc. In conclusion, zinc at the serosal side of piglet small intestinal epithelium attenuated 5-HT and VIP induced secretion in vitro. These in vitro studies indicate that in vivo there will be no positive acute effect of increasing luminal Zn concentration on secretagogue-induced chloride secretion and that zinc status at the serosal side of the epithelium has to be increased to reduce secretagogue-induced chloride secretion and thereby diarrhoea.     

Zinc reduces the electrophysiological responses in vitro to basolateral receptor mediated secretagogues in piglet small intestinal epithelium

Dietary zinc treatment has a preventive impact on diarrhoea in newly weaned piglets and in undernourished children. The mechanisms behind this effect of zinc are however, still not fully understood. The aim of the present study was to assess if zinc has a direct effect on porcine intestinal secretory responses to different secretagogues in vitro. The study included two Ussing chamber experiments, where the short circuit current responses to different secretagogues were measured in piglet small intestinal epithelium. Exp. 1 aimed to study the effect of increased zinc concentrations in the bathing media on the secretory responses to 5-HT and theophylline. The objective of exp. 2 was to study the effect of zinc in the bathing media on the secretory responses induced by vasoactive intestinal polypeptide (VIP), Substance P (SP), Carbachol, and theophylline. The results showed that there were significant decreasing effects of zinc on the secretion, stimulated by 5-HT, VIP and carbachol, from piglet intestinal epithelium in vitro, whereas the secretion caused by SP and theophylline was not significantly affected. The data indicate that the inhibitory mechanism of zinc ions may take place at the receptors situated at the basolateral membrane of the epithelial cells.     

Effects of orally administered probiotic Pediococcus acidilactici on the small and large intestine of weaning piglets. A qualitative and quantitative micro-anatomical study

Probiotic research has been approached, above all in recent years, by widely differing points of view, both for human and animal uses. Lactic acid bacteria release bacteriocins, and some of them may function as probiotic. The aim of the present study was to investigate the effects of dietary supplementation with the probiotic Pediococcus acidilactici on the piglet intestine, on circulating lymphocytes, and on aspects of piglet performance during the first 42 days after weaning. Sixteen female piglets were at weaning assigned to two dietary groups: Control (Ctr, 8 animals) and Pediococcus acidilactici supplemented (Pa, 8 animals). Piglets' growth was monitored from weaning to the end of the trial. On day 42 post-weaning, the piglets were slaughtered and small specimens from both ileum and cecum were examined with haematoxylin/eosin staining to ascertain structural details. Histometry was performed by villi and crypts measurements, as well as GALT measurements. Histochemical analyses were performed to investigate the intestinal mucins. Immunohistochemical analyses were used to visualize proliferating as well as apoptotic mucosal cells, and to identify mucosal macrophages and IgA producing cells. Intra-epithelial CD8+ T lymphocytes were identified and counted. Subsets of circulating T lymphocytes were analyzed by flow cytometry. Pediococcus acidilactici supplementation positively influenced weight and post-weaning average daily gain of treated piglets. Histometry showed an increase in villi height and crypts depth in Pa animals in comparison with controls. Treated piglets showed a larger number of proliferating enterocytes than controls. Intra-epithelial CD8+ T lymphocytes were scarcer in treated than in control piglets, likely in relation with catarrhal enteritis shown in the latter. We conclude that the studied supplementation was possibly able to protect the piglet small intestinal mucosa, improving local resistance to infections in the stressful weaning period.     

Impact of litter size,supplementary milk replacer and housing on the body composition of piglets from hyper-prolific sows at weaning

The modern hyper-prolific sow gives birth to 17 live-born piglets on average. An alternative strategy to nurse sows and artificial rearing may be providing milk replacer while letting all the piglets stay with their dam. However, milk replacer is of lower nutritional quality than sow milk and may reduce the body fat content of piglets who use milk replacer to compensate for low suckling success due to competition at the udder. Therefore, the aim of this study was to investigate the body composition at weaning of two random sow-reared piglets per litter from 93 litters by using the deuterium oxide dilution technique. The piglets were part of large study with a 2×2×2 factorial design of either 14 or 17 piglets from day 1 (LS: LS14/LS17) with or without access to milk replacer (MILK: -MILK/+MILK) and reared by crated or loose-housed sows (HOUSING: CRATE/ LOOSE). From behavioral observations day 21 in +MILK, piglets were divided according to their frequency of drinking milk replacer and suckling (Nutrition Source). Increasing LS from 14 to 17 reduced the average daily gain from 258 to 228 g/d and body fat % from 14.4 to 12.7% (P<0.01). In a two-way interaction between LS and HOUSNG, the body fat percentage was lower (P=0.04) and the water percentage tended to be higher (P=0.07) in LS17 CRATE compared to the other treatments (i.e. LS17 LOOSE, LS14 CRATE and LOOSE). There was no effect of MILK on piglet composition day 28 (P>0.1). In +MILK, the Nutrition Source affected piglet body composition (P<0.05) as piglets with low suckling frequency (LOW) had lower body fat and higher water content compared to piglets who had high suckling frequency (SUCKLE). Unexpectedly, drinking milk replacer in addition to suckling (MIXED) did not increase piglet body fat content. Relying mainly on milk replacer (CUP) caused body fat and water contents to be intermediate to piglets with high (SUCKLE and MIXED) and low suckling frequency (LOW). In conclusion, LS had a clear impact on piglet growth and body composition at weaning. In contrast, supplementation of milk and housing had only negligible impact on litter performance. Some individual piglets that had low frequency of sow milk intake benefitted from milk supplementation. Loose housing appeared to benefit piglet body fat at weaning but this was due to a greater piglet mortality.     

Increasing the frequency of co-mingling piglets during the lactation period alters the development of social behavior before and after weaning

The purpose of this study was to determine how increasing the frequency of co-mingling affected piglets' behavior development before and after weaning. Co-mingling once (CM1), piglets interacted with 1 unfamiliar litter Days 10-18 after birth; co-mingling twice (CM2), piglets interacted with 1 unfamiliar litter Days 10-14; and with another, Days 14-18. Control (CM0) piglets did not interact with unfamiliar litters before Day 18 (n = 16 litters per treatment). The study weighed piglets and recorded ear-injury scores throughout the experiment; however, there were no treatment differences. The CM2 piglets spent less time engaged in aggressive interactions (p < .05) than did CM0 piglets following mixing at weaning. During the social challenge, CM2 piglets spent more time in proximity to one another, had shorter latencies to first aggressive interaction, and spent less time fighting than did CM0 piglets (p < .05). During the social recognition test, CM2 piglets recognized the stimulus piglet at a faster rate than did CM0 piglets (p < .05). Overall, CM2 resulted in changes to some social behaviors compared with CM0 but not with CM1.     

Effect of organic and inorganic selenium sources in sow diets on colostrum production and piglet response to a poor sanitary environment after weaning

The objectives of this study were to determine the effect of the chemical form of selenium (Se) fed to sows (1) on production and immune quality of colostrum and (2) on piglet response to a deterioration of sanitary conditions after weaning. Twenty-two pregnant sows were assigned to receive a diet supplemented with 0.3 ppm Se from either sodium selenite (inorganic Se) or Se-enriched yeast (organic Se as Sel-Plex®; Alltech Inc., Nicholasville, KY, USA). Dietary treatments were applied during the last month of pregnancy and lactation. Blood samples were collected on sows before dietary treatment, on the day of weaning and 6 weeks later, and on three to five piglets within litters at birth, at weaning and 6 weeks post weaning. Whole blood was analysed for Se concentration. Colostrum samples were collected at 0, 3, 6 and 24 h post partum and milk samples on days 14 and 27 of lactation. Colostrum and milk were analysed for Se and immunoglobulin G (IgG) concentrations. At weaning, 40 pairs of littermate piglets were moved to rooms where sanitary conditions were good or purposely deteriorated. Piglets were reared individually and fed ad libitum. After 15 days, piglets and feed refusals were weighed and a blood sample was collected to measure plasma haptoglobin concentration. When sows were fed organic Se, Se concentrations were increased by 33% in colostrum (P < 0.05), 89% in milk (P < 0.001) and by 28% in whole blood of piglets at weaning (P < 0.001). Colostrum production during the 24 h after the onset of farrowing and IgG concentrations in colostrum and milk did not significantly differ between the two groups of sows. Weaned piglets reared in good sanitary conditions grew faster (P < 0.001) than piglets housed in poor conditions. Sanitary conditions did not influence mean plasma haptoglobin concentrations of piglets (P > 0.1). The source of Se fed to the dams did not influence piglet performance or haptoglobin concentrations after weaning. These findings confirm that, compared with inorganic Se, organic Se fed to the dam is better transferred to colostrum and milk, and consequently to piglets. They indicate that the Se source influences neither colostrum production nor IgG concentrations in colostrum, and that the higher Se contents of piglets does not limit the reduction of growth performance when weaning occurs in experimentally deteriorated sanitary conditions.     

Effects of dietary supplementation with grape seed procyanidins on nutrient utilisation and gut function in weaned piglets

Grape seed procyanidins (GSPs), widely known for their beneficial health properties, fail to bring about the expected improvement in piglets’ growth performance. The effects of dietary supplementation with GSPs on nutrient utilisation may be a critical influencing factor. Hence, the purpose of this study was to investigate the effects of dietary supplementation with GSPs on nutrient utilisation and gut function in weaned piglets. One hundred and twenty crossbred piglets were allocated randomly to four treatment groups, with three replicate pens per treatment and 10 piglets per pen. Each group was given one of the four dietary treatments: the basal diet (control group) or the basal diet with the addition of 50-, 100- or 150-mg/kg GSPs. The trial lasted 28 days. Faeces were collected from d 12 to 14 and from d 26 to 28 for measuring the coefficient of total tract apparent digestibility (CTTAD) of the nutrients. Blood samples were collected on d 14 and 28 for detecting the blood biochemical parameters. Two piglets per pen were slaughtered to collect the pancreas and intestinal digesta for evaluating the digestive enzyme activity and the coefficient of ileal apparent digestibility (CIAD) of the nutrients. On d 14 and 28, supplementation with 150-mg/kg GSPs significantly decreased the CTTAD of DM and CP in piglets. On d 14, GSPs supplementation at a concentration of 150 mg/kg led to a remarkable decrease in the CIAD of CP and gross energy (GE). On d 28, GSPs supplementation at a dose of 150 mg/kg generated a marked decline in the CIAD of DM, GE, CP and ether extract. Grape seed procyanidins supplementation at concentrations of 100 or 150 mg/kg inhibited the activities of lipase and amylase. In contrast, the jejunum mucosa maltase and sucrase activities increased due to the inclusion of GSPs at a concentration of 100 mg/kg in the piglet diet. Compared with the levels of the control group, the serum glucose and total protein levels were enhanced significantly by supplementation with GSPs at 100 mg/kg and reduced dramatically at 150 mg/kg. The serum diamine oxidase activity and endotoxin levels were decreased by GSPs supplementation in piglet diets. In conclusion, higher concentrations of GSPs in weaned piglet diets attenuated nutrient digestion and inhibited digestive enzyme activity; however, suitable concentrations of GSPs could promote brush-border enzyme activity, enhance serum glucose and total protein concentrations and decrease epithelial permeability.     

Piglets' weaning behavioural response is influenced by quality of human-animal interactions during suckling

The aim of this study was to compare the short-term post-weaning behaviour of piglets treated either neutrally or aversively during the suckling period. A total of 24 lactating sows and their litters were housed in different rooms according to treatment. A female experimenter (P1) was in charge of feeding and cleaning from days 10 to 27 after birth. For the aversive treatment (Aver), P1 was noisy, moved harshly and unpredictably and shouted frequently during routine cleaning of facilities and animal handling. For the neutral treatment (Neut), P1 used a soft tone of voice and was careful during the same routine. At weaning, the avoidance response of piglets to an approaching experimenter in a novel place was assessed in four piglets from each litter. Scores ranged from 1 (experimenter could touch piglet) to 4 (piglet escaped as soon as person moved). The test was repeated twice, with a 1-h interval, with P1, who wore blue trousers and white T-shirt, and a second handler unfamiliar to the piglets (P2, who wore blue coveralls). Thereafter, litters from the same treatment were mixed and housed in separate rooms, balanced for gender and live weight (n = 12 groups of 4 piglets/treatment). Behaviour time budgets were registered by scan sampling every 2-min, for 4 h per day, for 4 days. Piglets were weighed at birth, at weaning and on day 5. Effects of treatment and handler on responses to the avoidance test were analysed with non-parametric tests and effects of treatment with a mixed model for repeated measures. Avoidance score was higher for Aver than Neut piglets when tested with P1 (P = 0.04) but not with P2 (P = 0.8). When piglets' responses to the different handlers were compared within each treatment, no significant differences were found. Frequencies of resting were lower (P < 0.001), whereas escape attempts (P < 0.03), agonistic interactions (P < 0.02) and frequency of presence at feeder (P < 0.001) were higher in the Aver than in the Neut groups. Feed and water intake and weight gain did not differ between treatments. We conclude that 4-week-old piglets can discriminate a handler according to the nature of treatment received during suckling. In addition, piglets treated aversively seem to have more difficulty adapting to weaning than those treated neutrally during the suckling period.     

Group lactation from 7 or 14 days of age reduces piglet aggression at weaning compared to farrowing crate housing

Early life experiences can affect social behaviour in later life, but opportunities for socio-behavioural development are often overlooked in current husbandry practices. This experiment investigated the effects of rearing piglets in two-stage group lactation (GL) system from 7 or 14 days of age on piglet aggression at weaning. Three lactation housing treatments were applied to a total of 198 piglets from 30 litters of multiparous sows. All dams farrowed in standard farrowing crates (FCs). Group lactation litters were transferred with their dam at 7 (GL₇) or 14 days (GL₁₄) postpartum to GL pens (one pen of five sows at 8.4 m²/sow and one pen of seven sows at 8.1 m²/sow, per GL treatment). Farrowing crate litters remained with their dam in a single litter until weaning. At weaning, 10 to 14 piglets from two unfamiliar litters from the same housing treatment were mixed into pens (n=5 pens/treatment) and their behaviour was continuously recorded for 3.5 h. For each pen, the frequency of aggressive bouts (reciprocal and non-reciprocal aggression lasting <5 s), the frequency and duration of fights (reciprocal aggression lasting ⩾5 s) and bullying events (non-reciprocal aggression lasting ⩾5 s) were recorded, along with whether interactions involved familiar or unfamiliar piglets. Aggressive bouts delivered by FC piglets were approximately 1.5 and 3.0 times more frequent than that delivered by GL₇ and GL₁₄ piglets, respectively (40.5, 16.7 and 9.9 bouts/pig, respectively; P<0.05). Fighting was more frequent (1.6, 0.3 and 0.4 fights/pig, respectively; P<0.001) and fights were longer (83, 15 and 32 s fight/pig, respectively; P<0.001) between FC piglets than between GL₇ or GL₁₄ piglets. Bullying did not differ between housing treatments (P>0.05). GL₇ and GL₁₄ piglets engaged in a similar number of fights with unfamiliar as familiar piglets, but FC piglets had almost three times as many fights with unfamiliar than with familiar piglets (P<0.05). This experiment confirms the benefits of GL housing for pig social development. Further investigation is required to determine whether mixing before 14 days postpartum has implications for other indicators of animal welfare and productivity in a two-stage GL housing system.     

The behaviour and welfare of sows and piglets in farrowing crates or lactation pens

Temporary confinement during parturition and early postpartum may provide an intermediary step preceding loose housing that offers improvement in sow and piglet welfare. Three experiments were conducted to investigate the implications of replacing farrowing crates (FCs) with an alternative housing system from 3 days postpartum until weaning. In each experiment sows farrowed in FCs and were randomly allocated at day 3 of lactation to either a FC or a pen with increased floor space (lactation pen (LP)) until weaning. In experiment 1, piglet growth and sow and piglet skin injuries were recorded for 32 sows and 128 focal piglets in these litters. Behaviour around nursing and piglet behavioural time budgets were also recorded for 24 of these litters (96 focal piglets for time budgets). In experiment 2, measures of skin injury and behavioural time budgets were conducted on 28 sows and 112 focal piglets. The behavioural response of sows to piglet vocalisation (maternal responsiveness test (MRT)) was also assessed. In experiment 3, piglet mortality from day 3 of lactation until weaning was recorded in 672 litters over 12 months. While housing did not affect piglet weight gain in experiment 1, or piglet skin injuries in experiments 1 or 2, sows in both experiments sustained more injuries in LP than FC (experiment 1, 2.9 v. 1.4; experiment 2, 2.5 v. 0.8 lesions/sow; P<0.05). Sow–piglet interactions were more frequent in LP than FC at days 11 and 18 postpartum in both experiment 1 (day 11, 1.4% v. 1.2%; day 18, 1.7% v. 1.0% of observations; P=0.05) and 2 (day 11, 1.0% v. 0.3%; and at day 18 were 1.0% v. 0.6% of observations; P<0.01), and LP sows were more responsive in the MRT in experiment 2 (2 v. 0 median number of tests in which sows react, P<0.01). In experiment 1 piglets played more (0.7% v. 0.3% of observations, P=0.05) and manipulated others less (0.3% v. 0.7% of observations, P=0.04) in LP, but more piglets missed nursing bouts (0.2 v. 0.1 piglets/bout, P<0.01) compared with FC. There was no effect of housing on piglet mortality from day 3 of lactation until weaning in experiment 3 (0.63 and 0.64 deaths/litter for LP and FC, respectively, P>0.05). Thus, housing sows and litters in LP from day 3 of lactation minimises piglet mortality while improving maternal behaviour in sows and social behaviour in piglets.     

Effects of Weaning on Intestinal Upper Villus Epithelial Cells of Piglets

The intestinal upper villus epithelial cells represent the differentiated epithelial cells and play key role in digesting and absorbing lumenal nutrients. Weaning stress commonly results in a decrease in villus height and intestinal dysfunction in piglets. However, no study have been conducted to test the effects of weaning on the physiology and functions of upper villus epithelial cells. A total of 40 piglets from 8 litters were weaned at 14 days of age and one piglet from each litter was killed at 0 d (w0d), 1 d (w1d), 3 d (w3d), 5 d (w5d), and 7 d (w7d) after weaning, respectively. The upper villus epithelial cells in mid-jejunum were isolated using the distended intestinal sac method. The expression of proteins in upper villus epithelial cells was analyzed using the isobaric tags for relative and absolute quantification or Western blotting. The expression of proteins involved in energy metabolism, Golgi vesicle transport, protein amino acid glycosylation, secretion by cell, transmembrane transport, ion transport, nucleotide catabolic process, translational initiation, and epithelial cell differentiation and apoptosis, was mainly reduced during the post-weaning period, and these processes may be regulated by mTOR signaling pathway. These results indicated that weaning inhibited various cellular processes in jejunal upper villus epithelial cells, and provided potential new directions for exploring the effects of weaning on the functions of intestine and improving intestinal functions in weaning piglets.     

Influence of colostrum intake on piglet survival and immunity

Colostrum intake from birth to 24 h after the onset of parturition (T24) was estimated for 526 piglets from 40 litters. Plasma concentrations of immunoglobulin G (IgG), lactate, glucose and cortisol were determined at T24 for six piglets per litter. Plasma IgG concentration was also assayed at weaning (28 days) on the same piglets. Rectal temperature was measured at T24 on all piglets. Mortality was recorded until weaning and comparisons were made between piglets that died before weaning and those that were still alive at weaning. The piglets that died before weaning had lower birth weight, lower colostrum intake, lower weight gain between birth and T24, and had a lower rectal temperature, higher plasma cortisol concentration and lower plasma IgG and glucose concentrations at T24 than piglets still alive at weaning. In addition, a higher proportion of piglets that died before weaning had difficulty taking their first breath after birth and were affected by splayleg. Considering all piglets, colostrum intake was positively related to rectal temperature and plasma glucose concentration and negatively related to plasma cortisol concentration at T24. Plasma IgG concentration at T24 was explained by colostrum intake, IgG concentration in the ingested colostrum, birth weight and birth rank (P<0.0001). Plasma IgG concentration at weaning was related to plasma IgG concentration at T24 (r=0.54; P<0.0001) and to colostrum intake (r=0.32; P<0.0001). Finally, body weight was explained by colostrum intake, birth weight and age until 6 weeks of age (P<0.0001). These results show that colostrum intake is the main determinant of piglet survival through provision of energy and immune protection and has potential long-term effects on piglet growth and immunity.     

Zinc availability and digestive zinc solubility in piglets and broilers fed diets varying in their phytate contents, phytase activity and supplemented zinc source

The study was conducted to evaluate the effects of dietary zinc addition (0 or 15 mg/kg of Zn as inorganic or organic zinc) to three maize-soybean meal basal diets varying in their native Zn, phytic P contents and phytase activity (expressed in kg of feed: P- with 25 mg Zn and 1.3 g phytic P, P+ with 38 mg Zn and 2.3 g phytic P or P+/ENZ being P+ including 500 units (FTU) of microbial phytase per kg) in two monogastric species (piglets, broilers). Measured parameters were growth performance, zinc status (plasma, and bone zinc) and soluble zinc in digesta (stomach, gizzard and intestine). The nine experimental diets were fed for 20 days either to weaned piglets (six replicates per treatment) or to 1-day-old broilers (10 replicates per treatment). Animal performance was not affected by dietary treatments (P > 0.05) except that all P- diets improved body weight gain and feed conversion ratio in piglets (P < 0.05). Piglets fed P- diets had a better Zn status than those fed P+ diets (P < 0.05). In both species, Zn status was improved with supplemental Zn (P < 0.05), irrespective of Zn source. Phytase supplementation improved piglet Zn status to a higher extent than adding dietary Zn, whereas in broilers, phytase was less efficient than supplemental Zn. Digestive Zn concentrations reflected the quantity of ingested Zn. Soluble Zn (mg/kg dry matter) and Zn solubility (% of total Zn content) were highest in gizzard contents, which also presented lower pH values than stomach or intestines. The intestinal Zn solubility was higher in piglet fed organic Zn than those fed inorganic Zn (P < 0.01). Phytase increased soluble Zn in piglet stomach (P < 0.001) and intestine (P = 0.1), but not in broiler gizzard and intestinal contents. These results demonstrate (i) that dietary zinc was used more efficiently by broilers than by piglets, most probably due to the lower gizzard pH and its related higher zinc solubility; (ii) that zinc supplementation, irrespective of zinc source, was successful in improving animal's zinc status; and (iii) suggest that supplemented Zn availability was independent from the diet formulation. Finally, the present data confirm that phytase was efficient in increasing digestive soluble Zn and improving zinc status in piglets. However, the magnitude of these effects was lower in broilers probably due to the naturally higher Zn availability in poultry than in swine.     

Reproductive Performance of Sows Supplemented with Dietary L-carnitine over Three Reproductive Cycles

The effect of L-carnitine supplementation during pregnancy and lactation on the reproductive performance of sows was studied in two separate trials over three reproductive cycles. Both trials were identical in design and conduct but were performed with different animals. The trials comprised of a total of 127 sows (trial 1) and 100 sows (trial 2) which were divided into control and treatment groups. All animals were fed individually and received basic feed mixtures with low native carnitine concentrations. The rations of the sows in the treated group were supplemented with 125mg L-carnitine per head and day during pregnancy and 250mg L-carnitine per head and day during lactation. The animals of the control group received identical feed mixtures in identical amounts, but without the L-carnitine supplement. In the first trial, 212 litters were produced and evaluated for number and body weight of the animals, in the second trial, 173 litters were produced. L-carnitine supplementation significantly increased body weight gains of the sows between day 1 and day 85 of weaning. The number of born piglets, stillborn piglets and piglets fit for rearing was not influenced by dietary L-carnitine supplementation. However, L-carnitine supplementation significantly increased the weights of piglets and litters at birth, weight gains of litters during suckling and weights of litters at weaning. These effects of L-carnitine were seen in both trials; they were independent of the age of the sows and remained over three reproductive cycles in which the sows where continuously treated with L-carnitine. Overall, the study shows that dietary supplementation with L-carnitine during pregnancy and lactation improves the reproductive performance of sows over several reproductive cycles, independent of the age of the sows.     

L-Glutamate Supplementation Improves Small Intestinal Architecture and Enhances the Expressions of Jejunal Mucosa Amino Acid Receptors and Transporters in Weaning Piglets

L-Glutamate is a major oxidative fuel for the small intestine. However, few studies have demonstrated the effect of L-glutamate on the intestinal architecture and signaling of amino acids in the small intestine. The aim of this study was to investigate the effects of dietary L-glutamate supplementation on the intestinal architecture and expressions of jejunal mucosa amino acid receptors and transporters in weaning piglets. A total of 120 weaning piglets aged 35±1 days with an average body weight at 8.91±0.45 kg were randomly allocated to two treatments with six replicates of ten piglets each, fed with diets containing 1.21% alanine, or 2% L-glutamate. L-Glutamate supplementation increased the activity of glutamate oxaloacetate transaminase (GOT) in the jejunal mucosa. Also, the mRNA expression level of jejunal mucosa glutamine synthetase (GS) was increased by L-glutamate supplementation. The height of villi in duodenal and jejunal segments, and the relative mRNA expression of occludin and zonula occludens protein-1 (ZO-1) in jejunal mucosa were increased by dietary L-glutamate supplementation. L-Glutamate supplementation increased plasma concentrations of glutamate, arginine, histidine, isoleucine, leucine, methionine, phenylalanine and threonine. L-Glutamate supplementation also increased the relative mRNA expression of the jejunal mucosa Ca²⁺-sensing receptor (CaR), metabotropic glutamate receptor 1 (mGluR1) and metabotropic glutamate receptor 4 (mGluR4), and neutral amino acid transporter B⁰-like (SLC1A5) in the jejunal mucosa. These findings suggest that dietary addition of 2% L-glutamate improves the intestinal integrity and influences the expression of amino acid receptors and transporters in the jejunum of weaning, which is beneficial for the improvement of jejunal nutrients for digestion and absorption.     

Hematochemical parameters in calves before, during and after weaning to a regular diet

The Authors studied the changes of 17 blood parameters of calves before, during and after a traditional weaning. Concentrations of total protein, albumin, urea nitrogen, creatinine, glucose, cholesterol, triglycerides, alkaline phosphatase, total bilirubin and phosphorus were determined by an automated assay system; sodium, potassium and chloride by a flame photometer; calcium, magnesium, copper and zinc by an atomic absorption spectrophotometer. Observed changes can be referred to: 1) the change of the digestion (glucose); 2) the age of the subjects (alkaline phosphatase); 3) the increase of weight (creatinine); 4) the type of feeding (phosphorus, copper and zinc). Sodium, potassium, chloride, calcium and magnesium did not change during the weaning.     

Effects of alternative feed additives to medicinal zinc oxide on productivity,diarrhoea incidence and gut development in weaned piglets

The use of medicinal zinc oxide (ZnO) must be phased out by 2022, thus prompting an urgent need for alternative strategies to prevent diarrhoea in weaner piglets. The objectives of this study were to assess the impact on weaner piglet performance, diarrhoea incidence and gut development, when (1) dietary ZnO supplementation was substituted by alternative commercial products based on macroalgae, specific probiotics or synbiotics, or (2) dietary ZnO inclusion was reduced from 2500 to 1500 ppm. A total of 4680 DLY piglets (DanBred, Herlev, Denmark), weaned around 35 days of age, were randomly assigned according to sex and BW to six different dietary treatment groups. A basal diet was supplemented with no ZnO (NC= negative control), 2500 ppm ZnO (PC= positive control), 1500 ppm ZnO (RDZ= reduced dose of ZnO) or commercial macroalgae (OceanFeed™ Swine =OFS), probiotic Miya-Gold or synbiotic GærPlus products. The piglets entered and exited the weaner unit at ~7.0 and 30 kg BW, respectively. In-feed ZnO was provided the first 10 days post-weaning, while the alternative supplements were fed throughout the weaner period. As expected, the average daily feed intake, average daily weight gain (ADG), feed conversion ratio (FCR) and diarrhoea incidence were improved in the PC compared to NC group (P< 0.05) during phase 1 consistent with improved indices of villi development observed in subgroups of piglets sacrificed 11 days post-weaning. Reduction of ZnO to 1500 ppm lowered ADG (P< 0.05) and slightly increased incidence of diarrhoea during the first 10 days after weaning (but not later) without affecting FCR. None of the three alternative dietary additives, including a 10-fold increased dose of GærPlus than recommended, improved piglet performance, gut health and gut development above that of NC piglets. The OFS piglets sacrificed 11 days after weaning had significantly lower weights of hindgut tissue and contents compared to the PC group, consistent with antimicrobial activity of the product, which was detected from anaerobicin vitrofermentation. In conclusion, dietary ZnO supplementation during the first 10 days post-weaning may be reduced from 2500 to 1500 ppm without major negative implications for weaner piglet performance and health in herds under a high management level. However, none of the alternative dietary supplements were able to improve piglet performance or gut health, when ZnO was omitted from the diet.