Peri-weaning Period Research Articles

Prebiotic galactooligosaccharide improves piglet growth performance and intestinal health associated with alterations of the hindgut microbiota during the peri-weaning period

BackgroundWeaning stress reduces growth performance and health of young pigs due in part to an abrupt change in diets from highly digestible milk to fibrous plant-based feedstuffs. This study investigated whether dietary galactooligosaccharide (GOS), supplemented both pre- and post-weaning, could improve growth performance and intestinal health via alterations in the hindgut microbial community.MethodsUsing a 3 × 2 factorial design, during farrowing 288 piglets from 24 litters received either no creep feed (FC), creep without GOS (FG–) or creep with 5% GOS (FG+) followed by a phase 1 nursery diet without (NG–) or with 3.8% GOS (NG+). Pigs were sampled pre- (D22) and post-weaning (D31) to assess intestinal measures.ResultsCreep fed pigs grew 19% faster than controls (P < 0.01) prior to weaning, and by the end of the nursery phase (D58), pigs fed GOS pre-farrowing (FG+) were 1.85 kg heavier than controls (P < 0.05). Furthermore, pigs fed GOS in phase 1 of the nursery grew 34% faster (P < 0.04), with greater feed intake and efficiency. Cecal microbial communities clustered distinctly in pre- vs. post-weaned pigs, based on principal coordinate analysis (P < 0.01). No effects of GOS were detected pre-weaning, but gruel creep feeding increased Chao1 α-diversity and altered several genera in the cecal microbiota (P < 0.05). Post-weaning, GOS supplementation increased some genera such as Fusicatenibacter and Collinsella, whereas others decreased such as Campylobacter and Frisingicoccus (P < 0.05). Changes were accompanied by higher molar proportions of butyrate in the cecum of GOS-fed pigs (P < 0.05).ConclusionsGruel creep feeding effectively improves suckling pig growth regardless of GOS treatment. When supplemented post-weaning, prebiotic GOS improves piglet growth performance associated with changes in hindgut microbial composition.

PSV-21 Evaluation of the Effect of Daily Probiotic Administration on the Prevalence of Shiga Toxigenic E.Coli and Select Serum and Immune Parameters During Pre and Peri-Weaning Period in Goat Kids

Abstract Probiotics are microorganisms generally regarded as safe (GRAS) that have a beneficial effect when ingested by a host. While research on the benefits of probiotics in farm animals has mainly concentrated on major livestock species, little is documented on potential benefits in small ruminants. Probiotics in goats and sheep could offer a dual benefit of reducing pathogenic bacteria loads and resulting in improved immunity and overall health. In this study, we evaluated the effect of one-month daily commercial probiotic administration followed by weekly administration until weaning and daily administration for one week after weaning on select serum parameters, and also the prevalence of pathogenic E.coli in healthy pre-weaned goat kids beginning at two days of age. Overall, the general health of the animals in both groups remained the same throughout the study period. No significant difference in total lactic acid bacteria was detected between probiotic supplemented and control group. Probiotic administration generally improved the total serum protein and immune markers. The difference was significant after twenty-eight days of administration and two days after weaning for total serum protein and immune markers, respectively. Shiga toxin E.coli (STEC) was detected in both control and probiotic-treated goats in early life, but no significant differences were detected between treatment groups on prevalence. These results suggest that daily probiotic administration may have some health benefits in pre-weaned goats.

Farm management practices associated with influenza A virus contamination of people working in Midwestern United States swine farms

Indirect transmission of influenza A virus (IAV) contributes to virus spread in pigs. To identify farm management activities with the ability to contaminate farmworkers’ hands and clothing that then could be a source of virus spread to other pigs, we conducted a within-farm, prospective IAV surveillance study. Hands and clothes from farmworkers performing the activities of piglet processing, vaccination, or weaning were sampled before and after the activities were performed. Samples were tested by IAV rRT-PCR and virus viability was assessed by cell culture. A multivariate generalized linear model was used to detect associations of the activities with IAV contamination. Of the samples collected for IAV rRT-PCR testing, there were 16% (12/76) collected immediately after processing, 96% (45/48) collected after vaccination, and 94% (29/31) collected after weaning that tested positive. Samples collected immediately after vaccination and weaning, i.e., activities that took place during the peri-weaning period when pigs were about 3 weeks of age, had almost 6 times higher risk of IAV detection and had more samples IAV positive (p-value < 0.0001) than samples collected after processing, i.e., an activity that took place in the first few days of life. Both, hands and clothes had similar contamination rates (46% and 55% respectively, p-value = 0.42) and viable virus was isolated from both. Our results indicate that activities that involve the handling of infected piglets close to weaning age represent a significant risk for IAV dissemination due to the high level of IAV contamination found in farmworkers’ hands and coveralls involved in the activities. Biosecurity protocols that include hand sanitation and changing clothing after performing activities with a high-risk of influenza contamination should be recommended to farmworkers to control and limit the mechanical spread of IAV between pigs.

PSXIII-15 Effects of Bovine Colostrum Administration on Piglet Growth and Intestinal Health During the Lactation and Post-Weaning Periods

Abstract This study aimed to evaluate the potential of administering bovine colostrum to suckling and weanling piglets to modulate the growth, body composition, intestinal architecture, immunity, as well as remodeling and permeability. Twenty-four litters adjusted to 12 piglets each were selected at birth; one-half of them received liquid bovine colostrum (LC+) from d 5 to d 10, whereas the remaining litters did not receive any supplementation (LC-). Starting from d 11, all the litters received a creep feed either supplemented or not with 5% dehydrated bovine colostrum (BC+ and BC-, respectively). Animals were classified as “eaters” or “non eaters” according to their activity towards the feeders recorded by direct observation and presence of dietary marker (ferric oxide) in feces. At weaning (d 21), 16 LC+/BC+ and 16 LC-/BC- piglets (with an equal number of "eaters" and "non eaters" in each group) were selected and fed for 10 days with the same diets administered during lactation. Growth performance was recorded at d 0, 21 and 31. At d 31 bone mineral content, total body fat and lean contents were measured by dual X-ray absorptiometry; furthermore, animals were euthanized at d 31 and intestinal samples were collected to evaluate the intestinal morphology and concentration of TNFα, IL10, CXCL10, occludin, caspase 3 and proliferating cell nuclear antigen. Our results showed that LC+ and BC+ treatments increased creep feed consumption during lactation (P=0.01 and P=0.08, respectively) and affected litter weight at weaning (LC×BC interaction, P=0.04). Ten days after weaning, BC+ supplementation increased the intestinal villous to crypt ratio and reduced the occludin concentration (P&amp;lt;0.05). Piglets classified as creep feeding "eaters" showed greater intestinal occludin concentrations compared with "non eaters" animals (P=0.005). This study highlights the potential of bovine colostrum to increase piglet growth performance during lactation and affect the intestinal health in the peri-weaning period.

Heat shock protein A4 ablation leads to skeletal muscle myopathy associated with dysregulated autophagy and induced apoptosis

BackgroundMolecular chaperones assist protein folding, facilitate degradation of misfolded polypeptides, and thereby maintain protein homeostasis. Impaired chaperone activity leads to defective protein quality control that is implicated in multiple skeletal muscle diseases. The heat shock protein A4 (HSPA4) acts as a co-chaperone for HSP70. Previously, we showed that Hspa4 deletion causes impaired protein homeostasis in the heart. However, its functional role in skeletal muscle has not been explored.MethodsWe performed a comparative phenotypic and biochemical analyses of Hspa4 knockout (KO) mice with wild-type (WT) littermates.ResultsHSPA4 is markedly upregulated in regenerating WT muscle in vivo, and in differentiated myoblasts in vitro. Hspa4-KO mice are marked by growth retardation and increased variability in body weight, accompanied by 35% mortality rates during the peri-weaning period. The surviving Hspa4-KO mice experienced progressive skeletal muscle myopathy, characterized by increased number of muscle fibers with centralized nuclei, heterogeneous myofiber size distribution, inflammatory cell infiltrates and upregulation of embryonic and perinatal myosin heavy chain transcripts. Hspa4-KO muscles demonstrated an accumulation of autophagosome-associated proteins including microtubule associated protein1 light chain 3-II (LC3-II) and p62/sequestosome accompanied by increased number of TUNEL-positive nuclei.ConclusionsOur findings underscore the indispensable role of HSPA4 in maintenance of muscle integrity through contribution in skeletal muscle autophagy and apoptosis, which might provide a novel therapeutic strategy for skeletal muscle morbidities.

Phenotypical Variation of Ruminal Volatile Fatty Acids and pH during the Peri-Weaning Period in Holstein Calves and Factors Affecting Them.

Simple SummaryThe evolutionary course of rumen volatile fatty acids and their association with management factors during the peri-weaning period under field conditions have not been sufficiently investigated. There is a large phenotypical variability among calves in rumen parameters. There are several management factors affecting them, associated with a smooth rumen adaptation peri-weaning. The results enhance our knowledge about management practices that optimize ruminal adaptation during the weaning process.Two hundred and forty-three clinically healthy Holstein calves from eight commercial dairy farms were used to: (a) describe the evolutionary course of ruminal VFA concentration and pH during the peri-weaning period and (b) assess management factors affecting their phenotypical variation of these parameters. Management practices were recorded individually for each calf as these were not fixed within farms. Samples of ruminal fluid were collected at −7 d, 0 d, and 7 d relative to weaning. Gas chromatography was used to measure ruminal VFAs, and pH was measured on site. Linear mixed models for repeated measurements were used to assess the effects of management factors and their interactions. A large among-calves phenotypical variability was observed. Estimated marginal means showed that concentrations of acetate, butyrate, and total VFAs (but not of propionate) significantly decreased, while acetate propionate increased, from −7 d to 7 d. Age at weaning and body weight at −7 d were positively associated with total and several individual VFA concentrations. Group housing and late forage feeding pre-weaning were associated with higher VFA concentrations; the same factors, as well as step-weaning, were associated with pH values around 6. Feeding 7–8 L of milk replacer daily did not preclude a smooth transition, irrespective of weaning method.

Effect of weaning on serum biochemistry and establishment of reference intervals for peri-weaning period of Holstein calves

Biochemical profiles help vet practitioners identify problems in the weaning process when major metabolical changes occur. Reference intervals (RI) are useful in this respect but have not been established for this period. The objective of this study was twofold a) to identify the effect of time relative to weaning, adjusted for age at weaning, on the biochemical profile and b) to establish relevant RIs and assess the necessity of using time-specific RIs for the pre- and post-weaning periods instead of a single RI for this time frame. Two-hundred and forty-one clinically healthy Holstein calves from 9 commercial dairy farms were blood-sampled, at -7d, 0d and +7d relative to the day of weaning (0d). Samples were analyzed to determine the concentration of serum total protein (TP), albumin (ALB), globulin (GLOB), blood urea nitrogen (BUN), cholesterol (CHOL), triglyceride (TRIG), total bilirubin (tBIL), aspartate aminotransferase (AST), γ‐glutamyl transferase (γ-GT), β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA). The effect of time relative to weaning (TIME-W), adjusted for age at weaning and accounting for herd- and calf-level random variation, was assessed using linear mixed models. Reference intervals for total peri-weaning (PeriRI), pre-weaning (PreRI) and post-weaning (PostRI) periods were generated with the freeware Reference Value Advisor. Established RIs were visually compared with Adult cow RIs (AC). In order to test the agreement between PeriRI and PreRI/PostRI, the Cohen's kappa coefficient (κ) was used. The effect of TIME-W was significant for all parameters, except CHOL. Estimated marginal means for TP, ALB, GLOB, BUN, AST and BHB increased across TIME-W, while those of tBIL and NEFA decreased from 0d to +7d and of TRIG decreased from -7d to 0d. Total peri-weaning period RIs differ from AC for all parameters except γ-GT; PeriRI should be used for all biochemical parameters except for BUN, AST and BHB for which, PreRI and PostRI are preferable. The latter three parameters are potential candidates for assessing weaning management.

Weaning differentially affects mitochondrial function, oxidative stress, inflammation and apoptosis in normal and low birth weight piglets.

Weaning is associated with increased occurrence of infections and diseases in piglets. Recent findings indicate that weaning induces mitochondrial dysfunction and oxidative stress conditions that more severely impact smaller piglets. The objective of this study was to characterize the molecular mechanisms underlying these physiological consequences and the relation with systemic inflammatory status in both normal and low birth weight (NBW and LBW) piglets throughout the peri-weaning period. To conduct the study, 30 sows were inseminated, and specific piglets from their litters were assigned to one of two experimental groups: NBW (n = 60, 1.73 ± 0.01 kg,) and LBW piglets weighing less than 1.2 kg (n = 60, 1.01 ± 0.01 kg). Then, 10 piglets from each group were selected at 14, 21 (weaning), 23, 25, 29 and 35 days of age to collect organ and plasma samples. Specific porcine RT2 Profiler™ PCR Arrays related to mitochondrial function, oxidative stress, inflammation and apoptosis processes were first used to target genes that are modulated after weaning in NBW piglets (d 23 and d 35 vs. d 14). Expression of selected genes was evaluated by quantitative PCR. These analyses revealed that expression of inflammatory genes CXCL10 and CCL19 increased after weaning in intestinal mucosa, while expression of genes encoding subunits of the mitochondrial respiratory chain was downregulated in liver and kidney of both groups. Interestingly, major modulators of mitophagy (BNIP3), cell survival (BCL2A1) and antioxidant defense system (TXNRD2, GPx3, HMOX1) were found to be highly expressed in NBW piglets. The systemic levels of TNF-α and IL1-β significantly increased following weaning and were higher in NBW piglets. These results provide novel information about the molecular origin of mitochondrial dysfunction and oxidative stress observed in weaned piglets and suggest that clearance of dysfunctional mitochondria, antioxidant defenses and inflammatory response are compromised in LBW piglets.

Characterization of Different Commercial Dietary Supplements in the Peri-Weaning Period on Consumption and Growth Performance in C57Bl/6J Mice.

Simple SummaryThe current study compares two different commercially available nutritional supplements promoted as caloric support for weanlings for acceptability and effect on weight and survival in mouse pups and lactating dams in the peri-weaning phase with standard diet mash or no supplementation. Our aim was to provide an independent characterization of nutritional supplementation on survival and weight gain in a commonly used mouse strain. These factors influence animal welfare and are essential for the success of a general breeding program. Similarly, supplementation in the peri-weaning phase can alter early nutrition depending on type, which can introduce unintentional confounding that affects the reliability of subsequent experimental outcomes. This study was also designed to consider pragmatic aspects including timing, cost-effectiveness, diet composition, and practicality in an effort to identify supplements capable of optimally supporting pup growth and survival for various research applications in diverse animal use programs.This experiment was conducted to investigate the effects of common commercially available dietary supplementation in the peri-weaning period on feed intake, growth, and survival in C57Bl/6J mouse pups and lactating dams. A total of 96 pups and their dams were randomized to the control group or one of three nutritional supplement treatment groups: (i) control group without supplementation, or (ii) weanling-targeted Clear H2O gel (Gel), (iii) transgenic-targeted Bio-Serv dough (Dough), or (iv) dam diet as a mash (Chow), in the peri-weaning period (from 11 to 28 days). Stool was observed daily for a dye marker indicating supplement consumption. Pups were weaned at 21 days and followed for a total of 42 days. No pup morbidity or mortality was observed. There was a higher proportion of pups consuming dough and gel earlier than chow (p = 0.0091). The majority of treated pups (>95%) were consuming the supplement by day 23 (range 15–23), suggesting interplay between organoleptic properties of the supplement and pup maturity. All groups gained weight, with typical sexual dimorphism observed in the growth curves. Dough treatment led to significantly higher average daily gain in male pups (0.64 ± 0.03 g/d) as compared with controls (0.58 ± 0.03 g/d). The highest average daily gain in all groups was observed pre-weaning between days 21 and 28. Compared with controls, the weight gain slope was significantly higher in the Dough and Chow treatment groups and lower in Gel treatment groups, with a more pronounced effect in males. In this study, the composition of nutritional supplementation was the dominant factor in increasing the growth trend as opposed to energy density. Peri-weaning supplementation with Dough and Chow treatments improved pre- and post-growth performance in a comparable way and was more effective than Gel treatment during adaptation to solid feeding. Proper application of supplements to support weanlings can directly improve welfare and limit unintended experimental variability.

Impact of birth weight and neonatal nutritional interventions with micronutrients and bovine colostrum on the development of piglet immune response during the peri-weaning period

Immune system development of piglets is influenced by birth weight and colostrum and milk intake. Moreover, the dam transfer to piglets of vitamins A and D and copper, which play important role in immunity, is limited during lactation. In this study, we evaluated the potential of maternal and neonatal supplementations with vitamins A and D and copper, with or without neonatal supplementation of bovine colostrum (BC), to modulate the immune system development of low birth weight (LBW) and high birth weight (HBW) piglets during the peri-weaning period. Litters from 23 control sows (CONT) were assigned to one of the following treatments: 1) control (C); 2) oral administration at 2 and 8 days (d) of age of retinol-acetate, 25-hydroxyvitamin D and CuSO4 and exposure to UVB light for 15 min every second day from d 5 to d 21 (ADCu); 3) oral administration of dehydrated BC (4 g/d) from d 5 to d 10 (BC); 4) ADCu + BC. This experimental design was repeated with 24 sows fed extra daily supplements of 25-hydroxyvitamin D (4,000 IU), β-carotene (30,000 IU) and Cu-yeast (equivalent 45 mg of Cu) from 90 d of gestation until weaning at d 21 (SUPPL). Within each litter, 2 LBW and 2 HBW piglets were euthanized at d 16 and d 23 in order to characterize leukocyte subsets in mesenteric lymph nodes (MLN) and blood by flow cytometry, and to measure gene expression in the MLN and jejunal mucosa by qPCR. At d 16, results revealed that the percentages of γδ and cytotoxic T lymphocytes were significantly reduced in LBW compared to HBW piglets. The jejunal expression of interleukin (IL) 22 was also up-regulated, along with MLN expression of C-C Motif Chemokine Ligand 23, bone morphogenetic protein 2 and secreted phosphoprotein 1 (SPP1), whereas jejunal expression of tumor necrosis factor α was decreased in LBW piglets. At d 23, LBW piglets showed lower amounts of γδ T lymphocytes, higher percentages of CD3− and CD3−CD8α+CD16+ leukocytes (which include Natural killer cells) and lower jejunal expression of IL18. Furthermore, supplementation with BC increased the blood percentage of CD3−CD16+ leukocytes and reduced jejunal IL5 and MLN IL15 expression whereas supplementation with ADCu + BC increased jejunal TNF superfamily 13B and MLN SPP1 expression. Our results suggest that immune system development after birth differed between LBW and HBW piglets and that early dietary supplementation with BC and ADCu has the potential to modulate development of immune functions.

Distinct signaling and transcriptional pathways regulate peri-weaning development and cold-induced recruitment of beige adipocytes

Adipose tissue provides a defense against starvation and environmental cold. These dichotomous functions are performed by three distinct cell types: energy-storing white adipocytes, and thermogenic beige and brown adipocytes. Previous studies have demonstrated that exposure to environmental cold stimulates the recruitment of beige adipocytes in the white adipose tissue (WAT) of mice and humans, a process that has been extensively investigated. However, beige adipose tissue also develops during the peri-weaning period in mice, a developmental program that remains poorly understood. Here, we address this gap in our knowledge using genetic, imaging, physiologic, and genomic approaches. We find that, unlike cold-induced recruitment in adult animals, peri-weaning development of beige adipocytes occurs in a temperature- and sympathetic nerve-independent manner. Instead, the transcription factor B cell leukemia/lymphoma 6 (BCL6) acts in a cell-autonomous manner to regulate the commitment but not the maintenance phase of beige adipogenesis. Genome-wide RNA-sequencing (seq) studies reveal that BCL6 regulates a core set of genes involved in fatty acid oxidation and mitochondrial uncoupling, which are necessary for development of functional beige adipocytes. Together, our findings demonstrate that distinct transcriptional and signaling mechanisms control peri-weaning development and cold-induced recruitment of beige adipocytes in mammals.

Tissue-specific profiling reveals modulation of cellular and mitochondrial oxidative stress in normal- and low-birthweight piglets throughout the peri-weaning period

Weaning is known to induce important nutritional and energetic stress in piglets. Low-birthweight (LBW) piglets, now frequently observed in swine production, are more likely to be affected. The weaning period is also associated with dysfunctional immune responses, uncontrolled inflammation and oxidative stress conditions that are recognized risk factors for infections and diseases. Mounting evidence indicates that mitochondria, the main cellular sources of energy in the form of adenosine 5′ triphosphate (ATP) and primary sites of reactive oxygen species production, are related to immunity, inflammation and bacterial pathogenesis. However, no information is currently available regarding the link between mitochondrial energy production and oxidative stress in weaned piglets. The objective of this study was to characterize markers of cellular and mitochondrial energy metabolism and oxidative status in both normal-birthweight (NBW) and LBW piglets throughout the peri-weaning period. To conduct the study, 30 multiparous sows were inseminated and litters were standardized to 12 piglets. All the piglets were weighted at day 1 and 120 piglets were selected and assigned to 1 of 2 experimental groups: NBW (n = 60, mean weight of 1.73 ± 0.01 kg) and LBW piglets weighing less than 1.2 kg (n = 60, 1.01 ± 0.01 kg). Then, 10 piglets from each group were selected at 14, 21 (weaning), 23, 25, 29 and 35 days of age to collect plasma and organ (liver, intestine and kidney) samples. Analysis revealed that ATP concentrations were lower in liver of piglets after weaning than during lactation (P < 0.05) thus suggesting a significant impact of weaning stress on mitochondrial energy production. Oxidative damage to DNA (8-hydroxy-2′-deoxyguanosine, 8-OHdG) and proteins (carbonyls) measured in plasma increased after weaning and this coincides with a rise in enzymatic antioxidant activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD) (P < 0.05). Mitochondrial activities of both GPx and SOD are also significantly higher (P < 0.05) in kidney of piglets after weaning. Additionally, oxidative damage to macromolecules is more important in LBW piglets as measured concentrations of 8-OHdG and protein carbonyls are significantly higher (P < 0.05) in plasma and liver samples, respectively, than for NBW piglets. These results provide novel information about the nature, intensity and duration of weaning stress by revealing that weaning induces mitochondrial dysfunction and cellular oxidative stress conditions which last for at least 2 weeks and more severely impact smaller piglets.

PSVI-10 Detection of E. coli virulence genes during the pre-weaning and peri-weaning period in young meat goats

Abstract It has been postulated that changes in prevalence of E. coli isolates with particular virulence genes in animals may be affected by many factors including age, feed, geographical location and stress. The weaning period represents stressful stage during the growth of farm animals. To evaluate if weaning stress affects the prevalence of E. coli possessing virulence genes; shiga toxin (Stx), hemolysin (hly) and intimin (eae) in young meat goats, fecal samples were collected during pre-weaning period, day of weaning (0DPW), one day after weaning (1DPW), two days after weaning (2DPW) and 7 days after weaning (7DPW). Two hundred forty seven two E. coli isolates were screened for the virulence genes. All four virulence genes (Stx1, Stx2, Hly, and eae) evaluated were detected in E. coli during the peri-weaning period while only stx1, eae and hly were detected during the pre-weaning period. No Stx2 had been detected during the pre-weaning period. Both Stx1 and Hly frequency of detection increased significantly from 0DPW to 2DPW and then decreased on 7DPW. The Stx2 gene remained relatively the same between 0DPW and 7DPW. The frequency of eae detection was highest during the pre-weaning period but also increased significantly from 0DPW to 7DPW. Further characterization of peri-weaning isolates possessing either Stx2 or eae revealed that some belonged to serotypes important to animal and public health including O26, O103 and O146. We highlight a previously unreported finding on pattern of colonization by E. coli in young meat goats before and during peri-weaning period. This trend may be suggestive that strains of E. coli harboring specific virulence genes proliferate during times of stress such as weaning in young meat goats while others predominantly colonize very young animals. The significance of E. coli isolates possessing the various virulence genes in relation to animal health need further evaluation.

Dehydrated Alfalfa and Fresh Grass Supply in Young Rabbits: Effect on Performance and Caecal Microbiota Biodiversity.

Simple SummaryThe weaning of young rabbits is a critical period that is often accompanied by digestive troubles. Innovations in feeding strategy are urgently needed to preserve rabbit health and to reduce the use of antibiotics. We show here that providing dehydrated alfalfa during weaning is a promising solution to manage health status by favoring the establishment of a proper digestive microbiota.The improvement of rabbit gut microbiota by modifying nutritional components of the feed or favoring its early intake of feed has been previously investigated. The early administration of dehydrated alfalfa (A) or fresh grass (G) for rabbits, during the peri-weaning period (30 and 45 days of age), and their effect on performance and caecal microbiota compared to a standard diet (C) were evaluated. Until 15 days of age, nine litters/group were housed in the maternal cage and milked once per day. From 15 to 30 days, the young rabbits could consume both milk and solid feed (pelleted for C or supplemental feed for A and G). At 30 days of age, the rabbits were weaned and, until 45 days, were kept in single cages following the same dietary protocol. No significant changes were found in the milk intake or the individual weight of young rabbits at 30 and 45 days. The caecal Firmicutes/Bacteroidetes (bacterial phyla ratio) increased with age (from 2.43 to 6.05 on average, at 30 and 45 days). The Ruminococcaceae/Lachinospiraceae (bacterial family ratio) was highest in the A group at both ages, followed by G then C. The early administration of dehydrated alfalfa is a promising solution to improve health status by favoring an appropriate digestive microbiota.

Birth weight affects immune response of piglets during the peri-weaning period

Abstract Relationships between birth weight and a range of immune markers were studied in piglets during the peri-weaning period. A total of 47 sows and their respective litters adjusted to 12 piglets were used. Piglets were weighed after birth and within each litter 2 low weight (LW) and 2 high weight (HW) animals were identified: the average weight of the 2 groups was 1.12 and 1.81 ± 0.17 kg, respectively. Within litter, one couple of LW and HW piglets was sacrificed at 16 and 23 d of age, two days after weaning at day 21, to characterise different leukocyte subsets in mesenteric lymph nodes (MLN) and blood by flow cytometry. Jejunal mucosal and MLN samples were also collected to measure the expression of genes involved in immune response by qPCR. The percentage of blood γδT cells was higher in HW piglets before and after weaning (P=0.01 and P&amp;lt;0.001, respectively). At 16 d, LW animals had higher amounts of CD4+CD8+ T cells and dendritic cells in the blood (P=0.01 and P=0.04, respectively) and in MLN (P=0.02 and P=0.009 respectively), and lower count of blood cytotoxic T cells (P=0.01) than HW. Moreover, jejunal expression of TNFα was reduced in LW piglets (P=0.02), while MLN expression of CCL23, BMP2 and SPP1 was increased (P=0.003, P=0.002 and P=0.02, respectively). Two days after weaning (d 23), HW piglets had higher percentages of T cells (P=0.001) and lower amount of non-T cells (P=0.03) and natural killer cells (P=0.04) in blood compared to LW animals. These data revealed that piglet birth weight affects the proportion of leukocyte subsets in different tissues and the expression of genes involved in the immunity. Globally, our results suggest that the development of the immune system after birth differed between LW and HW piglets.

Risk factors associated with exposure to bovine respiratory disease pathogens during the peri-weaning period in dairy bull calves

BackgroundBovine respiratory disease (BRD) remains among the leading causes of death of cattle internationally. The objective of this study was to identify risk factors associated with exposure to BRD pathogens during the peri-weaning period (day (d)-14 to d 14 relative to weaning at 0) in dairy bull calves using serological responses to these pathogens as surrogate markers of exposure.Clinically normal Holstein-Friesian and Jersey breed bull calves (n = 72) were group housed in 4 pens using a factorial design with calves of different breeds and planes of nutrition in each pen. Intrinsic, management and clinical data were collected during the pre-weaning (d − 56 to d − 14) period. Calves were gradually weaned over 14 days (d − 14 to d 0). Serological analysis for antibodies against key BRD pathogens (BRSV, BPI3V, BHV-1, BHV-4, BCoV, BVDV and H. somni) was undertaken at d − 14 and d 14. Linear regression models (for BVDV, BPI3V, BHV-1, BHV-4, BCoV and H. somni) and a single mixed effect random variable model (for BRSV) were used to identify risk factors for changes in antibody levels to these pathogens.ResultsBRSV was the only pathogen which demonstrated clustering by pen. Jersey calves experienced significantly lower changes in BVDV S/P than Holstein-Friesian calves. Animals with a high maximum respiratory score (≥8) recorded significant increases in H. somni S/P during the peri-weaning period when compared to those with respiratory scores of ≤3.Haptoglobin levels of between 1.32 and 1.60 mg/ml at d − 14 were significantly associated with decreases in BHV-1 S/N during the peri-weaning period. Higher BVDV S/P ratios at d − 14 were significantly correlated with increased changes in serological responses to BHV-4 over the peri-weaning period.ConclusionsHaptoglobin may have potential as a predictor of exposure to BHV-1. BRSV would appear to play a more significant role at the ‘group’ rather than ‘individual animal’ level. The significant associations between the pre-weaning levels of antibodies to certain BRD pathogens and changes in the levels of antibodies to the various pathogens during the peri-weaning period may reflect a cohort of possibly genetically linked ‘better responders’ among the study population.

Improving welfare and production in the peri-weaning period: Effects of co-mingling and intermittent suckling on the stress response, performance, behaviour, and gastrointestinal tract carbohydrate absorption in young pigs

We investigated the effect of different pre-weaning interventions on performance, aspects of behaviour, and selected neuroendocrine, inflammatory and immune indices in 593 weanling pigs (59 litters, weaning age 22 ± 1.7). Measurements were taken at various time points two weeks before and after weaning. Sugar absorption tests (20% mannitol and 20% galactose solutions) were used to assess gastrointestinal tract (GIT) absorptive capacity. One week before weaning, litters were either co-mingled (CoM) for 8h daily with another litter or not co-mingled (NoCoM). Half of the litters were also subjected to intermittent suckling (IS) involving separation from their sow for 8h daily and the other half remained with their sow (NoIS). Hence, four treatments were produced in a 2×2 factorial design; (1) CoM IS (n = 16 litters), (2) CoM NoIS (n = 14 litters), (3) NoCoM IS (n = 16 litters), (4) NoCoM NoIS (n = 13 litters). Measurements are compared within each of the main effects (CoM or IS) unless otherwise stated. Acute weaning stress was evidenced by increases in cortisol, haptoglobin and N: L ratios when data were combined (P < 0.001). However, there were tendencies (P < 0.1) for lower cortisol in IS pigs and higher N: L ratios in CoM pigs at weaning. While CoM did not affect performance before weaning, growth (P < 0.05), feed intake (P < 0.05) and body weight (P < 0.05) were reduced in CoM pigs 7–14 days after weaning. One week of IS before weaning improved feed intake before weaning (P < 0.01), resulting in better growth (P = 0.01) and a tendency (P < 0.1) for a higher feed intake 2–7 days after weaning. Co-mingled piglets had more scratches 4 days before weaning (P < 0.001), but tended to have fewer scratches 2 days after weaning (P < 0.1). Pigs exposed to either IS or CoM displayed more sleeping behaviour the day after weaning (P < 0.01 and P < 0.001). A higher mannitol absorption was evident in CoM NoIS pigs 3 days after weaning (P < 0.01), and galactose absorption was reduced in IS pigs 3 days before weaning (P < 0.05) and tended to be reduced 3 days after weaning (P < 0.1), likely reflecting a GIT adaptive response. Overall, despite improvements in mannitol absorption and behaviour, there was no beneficial effect of CoM on performance after weaning. Alternatively, IS improved behaviour and performance during the first week after weaning.

Developmental window of sensorineural deafness in biotinidase-deficient mice.

Biotinidase deficiency is an autosomal recessively inherited disorder that results in the inability to recycle the vitamin, biotin. If untreated, the disorder can result in a range of neurological and cutaneous symptoms, including sensorineural deficits and deafness. To understand early mechanistic abnormalities that may precede more generalized and nonspecific effects of metabolic deficits such as weight loss and acidosis, we have analyzed auditory brainstem responses (ABRs) in biotinidase-deficient knockout (Btd -/- ) mice in the periweaning period with or without dietary biotin supplementation. We find significant increases in the latency of wave V of the ABR elicited by pure tone stimuli at one octave intervals, which precede substantial increases in ABR thresholds. Finer interpeak latency analyses of these changes indicate they are confined to the latter ABR waves associated with the CNS and likely reflect slowed brainstem transmission time. In contrast, peripheral nervous system conduction velocity appears normal. Further, we find that biotin-supplementation after the onset of symptoms reverses the latency shifts, which has significant relevance for early treatment in patients. Finally, ABR latencies in Btd -/- mice fed a biotin-supplemented diet for the first month of life appear refractory to transmission time slowing during a subsequent bout of biotin deficiency. These data suggest a transient vulnerability window for biotin deficiency in the auditory brainstem. Finally, we also observe a developmental vulnerability window involving follicular melanosome production or melanocyte survival. Sensorineural deafness precedes peripheral hearing loss in developmental biotinidase deficiency and is transient if rescued by dietary biotin within a short developmental window.

Development-dependent behavioral change toward pups and synaptic transmission in the rhomboid nucleus of the bed nucleus of the stria terminalis

Sexually naïve male C57BL/6 mice aggressively bite unfamiliar pups. This behavior, called infanticide, is considered an adaptive reproductive strategy of males of polygamous species. We recently found that the rhomboid nucleus of the bed nucleus of the stria terminalis (BSTrh) is activated during infanticide and that the bilateral excitotoxic lesions of BSTrh suppress infanticidal behavior. Here we show that 3-week-old male C57BL/6 mice rarely engaged in infanticide and instead, provided parental care toward unfamiliar pups, consistent with observations in rats and other rodent species. This inhibition of infanticide at the periweaning period is functional because the next litter will be born at approximately the time of weaning of the previous litter through maternal postpartum ovulation. However, the mechanism of this age-dependent behavioral change is unknown. Therefore, we performed whole-cell patch clamp recordings of BSTrh and compared evoked neurotransmission in response to the stimulation of the stria terminalis of adult and 3-week-old male mice. Although we were unable to detect a significant difference in the amplitudes of inhibitory neurotransmission, the amplitudes and the paired-pulse ratio of evoked excitatory postsynaptic currents differed between adult and 3-week-old mice. These data suggest that maturation of the synaptic terminal in BSTrh that occurred later than 3 weeks after birth may mediate by the adaptive change from parental to infanticidal behavior in male mice.

Intermittent Suckling Causes a Transient Increase in Cortisol That Does Not Appear to Compromise Selected Measures of Piglet Welfare and Stress.

Simple SummaryThis study assessed the effects intermittent suckling (IS) had on physiological and behavioral indices of piglets before and after weaning. Piglets were allocated to either a control treatment (conventional weaning) or an IS treatment (separation from the sow for 8 h per day starting the week before weaning). Apart from an initial peak in cortisol at the start of IS, piglets subjected to IS did not show physiological changes suggestive of a chronic stress response before and after weaning. The event of weaning still caused a decrease in growth rate and an increase in white blood cell parameters in both treatment groups. However, the IS piglets tended to gain more weight in the second half of the week after weaning. The results of this study suggest that short periods of separation (e.g., 8 h/day) do not appear to compromise piglet welfare over the peri-weaning period.This study tested the hypothesis that piglets subjected to intermittent suckling (IS) would show changes in physiological and behavioral indices indicative of compromised welfare in the peri-weaning period. A total of 21 primiparous sows and their litters were allocated to either a control treatment (n = 10) where piglets were weaned conventionally, or an IS treatment (n = 11) where piglets were separated daily from their sows for 8 h starting the week before weaning. Performance, physiological and behavioral measures were taken at various time points during the week before and after weaning. Plasma cortisol levels were higher (p = 0.01) in IS piglets 7 d before weaning. Regardless of treatment, the N:L ratio at 3 d and 7 d after weaning was higher (p < 0.05) than that at 1 d before weaning. The IS piglets ate more creep feed during lactation (p < 0.05), and there was a tendency for the IS piglets to gain more weight between 3 d and 7 d after weaning (p < 0.1). This study showed that, aside from an increase in cortisol at the start of IS, piglets subjected to IS did not display physiological or behavioral changes indicative of compromised welfare.