Post-weaning Stage Research Articles

Influence of Feeding Weaned Piglets with Laminaria digitata on the Quality and Nutritional Value of Meat.

Laminaria digitata is a novel feedstuff that can be used in pig diets to replace conventional feedstuffs. However, its resilient cell wall can prevent the monogastric digestive system from accessing intracellular nutrients. Carbohydrate-active enzyme (CAZyme) supplementation is a putative solution for this problem, degrading the cell wall during digestion. The objective of this work was to evaluate the effect of 10% L. digitata feed inclusion and CAZyme supplementation on the meat quality and nutritional value of weaned piglets. Forty weaned piglets were randomly allocated to four experimental groups (n = 10): control, LA (10% L. digitata, replacing the control diet), LAR (LA + CAZyme (0.005% Rovabio® Excel AP)) and LAL (LA + CAZyme (0.01% alginate lyase)) and the trial lasted for two weeks. The diets had no effect on any zootechnical parameters measured (p > 0.05) and meat quality traits, except for the pH measured 24 h post-mortem, which was higher in LAL compared to LA (p = 0.016). Piglets fed with seaweed had a significantly lower n-6/n-3 PUFA ratio compared to control, to which the higher accumulation of C20:5n-3 (p = 0.001) and C18:4n-3 (p < 0.0001) contributed. In addition, meat of seaweed-fed piglets was enriched with bromine (Br, p < 0.001) and iodine (I, p < 0.001) and depicted a higher oxidative stability. This study demonstrates that the nutritional value of piglets’ meat could be improved by the dietary incorporation of L. digitata, regardless of CAZyme supplementation, without negatively affecting growth performance in the post-weaning stage.

Microbiome network traits in the rumen predict average daily gain in beef cattle under different backgrounding systems

BackgroundBackgrounding (BKG), the stage between weaning and finishing, significantly impacts feedlot performance in beef cattle; however, the contributions of the rumen microbiome to this growth stage remain unexplored. A longitudinal study was designed to assess how BKG affects rumen bacterial communities and average daily gain (ADG) in beef cattle. At weaning, 38 calves were randomly assigned to three BKG systems for 55 days (d): a high roughage diet within a dry lot (DL, n = 13); annual cover crop within a strip plot (CC, n = 13); and perennial pasture vegetation within rotational paddocks (PP, n = 12), as before weaning. After BKG, all calves were placed in a feedlot for 142 d and finished with a high energy ration. Calves were weighed periodically from weaning to finishing to determine ADG. Rumen bacterial communities were profiled by collecting fluid samples via oral probe and sequencing the V4 region of the 16S rRNA bacterial gene, at weaning, during BKG and finishing.ResultsRumen bacterial communities diverged drastically among calves once they were placed in each BKG system, including sharp decreases in alpha diversity for CC and DL calves only (P < 0.001). During BKG, DL calves showed a substantial increase of Proteobacteria (Succinivibrionaceae family) (P < 0.001), which also corresponded with greater ADG (P < 0.05). At the finishing stage, Proteobacteria bloomed for all calves, with no previous alpha or beta diversity differences being retained between groups. However, at finishing, PP calves showed a compensatory ADG, particularly greater than that in calves coming from DL BKG (P = 0.02). Microbiome network traits such as lower average shortest path length, and increased neighbor connectivity, degree, number and strength of bacterial interactions between rumen bacteria better predicted ADG during BKG and finishing than variation in specific taxonomic profiles.ConclusionsBacterial co-abundance interactions, as measured by network theory approaches, better predicted growth performance in beef cattle during BKG and finishing, than the abundance of specific taxa. These findings underscore the importance of early post weaning stages as potential targets for feeding interventions that can enhance metabolic interactions between rumen bacteria, to increase productive performance in beef cattle.

Expression of D5 dopamine receptors in the lateral ventricle walls during post-weaning rat development.

Even before the first synapses appear, neurotransmitters and their receptors are present in the developing brain, regulating the cell fate of neuronal progenitors in neurogenic niches, such as the lateral ventricle. In particular, dopamine appears to play a pivotal role in the neurogenesis of the subventricular zone by controlling the proliferation and differentiation of progenitors through activation of different receptors. Although dopamine receptor 5 (D5R) is expressed prenatally, there is little information regarding its role in either pre- or postnatal forebrain development. To examine the role of D5Rs in neurogenesis in the rat lateral ventricle subventricular zone (V-SVZ), we immunohistochemically defined D5R expression, as well as BrdU incorporation in progenitor cells of various post-weaning stages (Post-natal day (P) 20 until P80). We found that the level of proliferating cells is stable from postnatal day 20 until 50, and then declines sharply on P80. Concomitantly, D5R is expressed in all ages examined, but we detected a progressive decrease in the density of D5R+ cells from P40 until P80. Moreover, double immunostaining for BrdU and D5R revealed that proliferating cells in V-SVZ also express D5R. Collectively, our data suggest that D5R is expressed in the post-weaning V-SVZ of rat at least until P80, and its expression pattern coincides with that of proliferating cells in the V-SVZ, hinting at a possible role of D5Rs in the regulation of neuronal progenitor division/differentiation.

Influences of the Seasons of the Year and Physiographic Regions on the Levels of Calcium, Copper and Zinc in the Hoof Capsule of Foals Pre- and Postweaning Raised in Native Pasture

This study evaluated the levels of calcium (Ca), copper (Cu) and zinc (Zn) in the hoof of Criollo foals, pre- and postweaning, correlating them with the concentrations of these inorganic chemical compounds in soil and pasture in the different seasons of the year. We used 41 preweaning foals and 28 postweaning foals. Seventeen forage samples were collected in four seasons, later 10 soil samples per property in five distinct physiographic regions (Santa Maria, Dilermando de Aguiar, Jaguarão, Arroio Grande and Pelotas). There was variability in Ca, Cu and Zn concentrations in the hoof foal between distinct physiographic regions (P < .05), and between seasons. There was no association of preweaning and postweaning Ca levels with forage in the different physiographic regions. The concentrations of Cu and Zn showed positive association (R = 0.69, 0.43; P < .05) with the native pastures in the different physiographic regions in preweaning. In postweaning, only Cu was positively associated (R = 0.74; P < .05). Different season and physiographic regions influence the levels of Ca, Cu and Zn in the hoof capsule and native pasture during the pre- and postweaning stages.

Association of single nucleotide polymorphism in leptin gene with growth traits of Jamunapari goat

The current study sought to identify single nucleotide polymorphisms (SNPs) in the leptin gene and investigate their relationship with growth traits in goats. Phenotypic data for birth weight (BW), weaning weight (WW), body weight at six month (6MW), body weight at nine month (9MW) and body weight at twelve month (12MW) from Jamunapari goats were recorded. Seven pairs of primers were designed to amplify the leptin gene spanning promoter, exonic, intronic and 3’ UTR regions by polymerase chain reaction. High Resolution Melting (HRM) was employed for genotyping, and DNA sequencing was utilized to mining SNPs. Four novel SNPs at g.584C&gt;T, g.4226T&gt;C, g.4158T&gt;C and g.4133T&gt;A were identified in promoter region and 3' UTR region of leptin gene. Statistical analysis revealed that SNPs at g.584C&gt;T was associated with weaning and post weaning stages of growth. Moreover, goats with the CT genotype had higher body weight at WW, 6MW, 9MW and 12MW than those with CC genotype. The results of this study demonstrated that SNPs in leptin gene was significantly associated with growth traits in goat. These findings suggest that an SNP in the caprine leptin gene could be one of the candidates for improving body weight in the Jamunapari goat.

PSX-A-22 Late-Breaking: Rumen microbiome composition and microbe network dynamics in beef cattle predict finishing performance under different backgrounding systems

Abstract Backgrounding (BKG) impacts growth and finishing performance in beef cattle. However, specific microbiome contributions to growth performance during this period, considering different BKG systems, remain unknown. A longitudinal study was designed to characterize the rumen microbiome and average daily gain (ADG) of Angus and Angus x Simmental calves (n = 38) placed under different BKG systems for 55 d after weaning: DL: a high roughage diet within a dry lot and CC: annual cover crop within a strip and PP, while a third group, PP: remained on perennial pasture vegetation within rotational paddocks, just as before weaning. After BKG, calves went to a feedlot for 142 d and finished with a high energy ration. Rumen bacterial communities were profiled by collecting fluid samples via oral probe, and sequencing the V4 region of the 16S rRNA bacterial gene, at weaning, during backgrounding and finishing. For calves moved to CC and DL BKG, bacterial composition diverged drastically, including sharp decreases in bacterial diversity (P &amp;lt; 0.001), while PP claves conserved more stable diversity patterns. During BKG, DL calves also showed the greatest ADG (P &amp;lt; 0.05), which coincided with increased abundance of taxa affiliated to the Aeromondales (Succinivibrio, Succcinimonas and Ruminobacter) (P &amp;lt; 0.001). However, once in the finishing phase, PP calves showed compensatory ADG, with significantly higher values, particularly compared with calves on DL BKG (v = 0.02). Network theory analyses were concordant with these patterns, highlighting the importance of understanding microbe-microbe interactions at early developmental stages to predict finishing performance. These results indicate that rumen microbes and their network interactions during backgrounding successfully predict finishing performance in beef cattle, underscoring the importance of early post weaning stages as potential targets for feeding interventions that can modulate the rumen microbiome to enhance lifelong animal performance.

Accurate assessment of body weights using morphometric measurements in Landlly pigs.

The aim of the study was to evaluate 16 novel morphometric traits of Landlly piglets at weaning (6weeks) and post weaning (8weeks) stage and to predict corresponding body weight from the measurements. A total of 279 Landlly piglets (n = 279, 75% Landrace + 25% Ghurrah crosses) were enrolled in this study. Body length, heart girth, paunch girth, height at wither, height at back, rump width, thigh circumference, neck circumference, and body depth had high correlation coefficients (0.8-0.97) with body weight at both the stages. Stepwise regression showed that body length and heart girth contributed most in prediction of both body weights while height at wither for body weight at 6weeks and neck circumference for body weight at 8weeks was the next highest contributing trait. Akaike's information criterion, Bayesian information criteria, adjusted R2, concordance correlation coefficient, bias correction factor, modeling efficiency, and coefficient of model determination were used to determine the most appropriate model for the prediction of body weight. Model containing body length and heart girth was fitted best to data for prediction of body weight at both weaning and post weaning stage with adjusted R2 values of 0.94 and 0.96, respectively. Hence, 2 different models were proposed for accurately predicting body weight in Landlly pigs at 6 and 8weeks.

The burden of size and growth for the juveniles of large mammalian herbivores: Structural and functional constraints in the feeding biology of juveniles relative to adults in red kangaroos, Osphranter rufus.

Juvenile mammals in their postweaning developmental stages face many challenges in transitioning to adulthood. Among large grazing species such as ruminant bovids and cervids, an overarching challenge is acquiring and processing sufficient nutrients to survive and grow, with a gut that may not yet be fully developed. Marsupial kangaroos of Australia face similar challenges; they also digest vegetation by fermentation in a large foregut. In red kangaroos, Osphranter rufus (=Macropus rufus), the dominant species of Australia's arid interior, females may breed continuously; however, juvenile recruitment to the adult population is irregular and coincident with sporadic rainfall.As compared with adult females, the nutritional requirements of juvenile O. rufus are high in relation to their body mass (BM), largely due to the cost of their rapid growth. We examined processes that juveniles have in their morphology, physiology, and behaviors to meet their elevated nutritional needs, by comparing recently weaned juveniles of both sexes and adult female O. rufus in their desert habitat. Features studied include relative body sizes, relative dimensions, and capacities of principal gut regions, the foregut, small intestine, caecum, and large intestine with rectum. Also examined were digesta attributes and rates of digesta excretion. Additionally, the rates of change in skull parameters and dental characteristics to maturity were assessed. Field determinations of diet choice were made for both age classes.In juveniles, the content masses of major gut structures were related to body mass (BM), as were those of adult females, that is, ~BM1.0. In both age classes, the digesta mass of the foreguts exceeded 75% of the total digesta mass. Diets of both juvenile and adult O. rufus largely focused on grasses. Juveniles had higher rates of digesta excretion while foraging than adults. In addition, the foregut contents in juveniles occupy proportionally less of the total gut than in adult females. Together, the higher excretion rate and smaller relative foregut of juveniles suggest that they necessarily focus on forage that can be rapidly digested, such as young, green grasses, or herbage.Comparison of the skulls of juveniles and adults revealed how this harvest can occur. Relative to BM, juveniles had skulls of larger volume than adults. Additionally, during growth the skull lengthens proportionally faster than increasing BM. By weaning, the dimensions of the incisor bite of juveniles neared those of adult females. The area of wear on premolars/molars increased only slowly relative to the development of incisors, further pointing to juveniles selecting more digestible forage than adults. The intermittent availability of such forage, principally young grasses, appears key to the significant recruitment into the O. rufus population in their arid habitat.

Influence of dietary Spirulina inclusion and lysozyme supplementation on the longissimus lumborum muscle proteome of newly weaned piglets

Arthrospira platensis (Spirulina) is a microalga with a high content of crude protein. It has a recalcitrant cell wall that limits the accessibility of the animal endogenous enzymes to its intracellular nutrients. Enzymatic supplementation aiming to degrade cell walls could benefit microalgae digestibility. The objective of this study was to evaluate the impact of dietary Spirulina and lysozyme supplementation over the muscle proteome of piglets during the post-weaning stage. Thirty piglets were randomly distributed among three diets: control (no microalga), SP (10% Spirulina) and SP + L (10% Spirulina +0.01% lysozyme). After 4 weeks, they were sacrificed and samples of the longissimus lumborum muscle were taken. The muscle proteome was analysed using a Tandem Mass Tag (TMT)-based quantitative approach. A total of 832 proteins were identified. Three comparisons were computed: SP vs Ctrl, SP + L vs Ctrl and SP + L vs SP. They had ten, four and twelve differentially abundant proteins. Glycogen metabolism and nutrient reserves utilization are increased in the SP piglets. Structural muscle protein synthesis increased, causing higher energy requirements in SP + L piglets. Our results demonstrate the usefulness of proteomics to disclose the effect of dietary microalgae, whilst unveiling putative mechanisms derived from lysozyme supplementation. Data available via ProteomeXchange with identifier PXD024083. SignificanceSpirulina, a microalga, is an alternative to conventional crops which could enhance the environmental sustainability of animal production. Due to its recalcitrant cell wall, its use requires additional measures to prevent anti-nutritional effects on the feeding of piglets in the post-weaning period, during which they endure post-weaning stress. One of such measures could be CAZyme supplementation to help degrade the cell wall during digestion. Muscle proteomics provides insightful data on the effect of dietary microalgae and enzyme activity on piglet metabolism.

Immunohistochemical localization of VEGFR-2 in mouse mammary gland during reproductive cycle.

Objective:The objective of this study was to obtain an insight into the role of the vascular endothelial growth factor (VEGF) in pregnancy-associated mammary epithelial development and angiogenesis. However, we examined the primary VEGF receptor (VEGFR-2) in the mouse mammary cycle.Materials and Methods:The virgin (10–12 weeks), days 10 and 18 of pregnancy (P-10 and P-18), days 0, 5, 10, and 20 of lactation (L-0, L-5, L-10, and L-20), and days 5 and 10 of post-weaning (W-5 and W-10) stage were all used in this study. Immunohistochemistry and Western blotting were carried out on mammary tissues taken from three mice at each stage.Results:VEGFR-2 was detected immunohistochemically in the cytoplasm of mammary epithelial and endothelial cells. Immunostaining for VEGFR-2 was consistently positive in mammary endothelial cells across all stages, whereas staining intensity in epithelial cells varied across the mammary cycle. Additionally, immunoblot analysis indicated a 220 kDa unique band of VEGFR-2 protein at all stages of the mammary cycle, with the maximum expression reported toward the end of pregnancy and gradually decreasing toward the end of lactation.Conclusion:In conclusion, the presence of VEGFR-2 in the mammary epithelium in addition to the endothelium suggests that VEGF plays an autocrine and paracrine role in the development, proliferation, and differentiation of the mammary epithelium during pregnancy.

Quantification, description and international comparison of antimicrobial use on Irish pig farms

BackgroundThere is concern that the use of antimicrobials in livestock production has a role in the emergence and dissemination of antimicrobial resistance in animals and humans. Consequently, there are increasing efforts to reduce antimicrobial use (AMU) in agriculture. As the largest consumer of veterinary antimicrobials in several countries, the pig sector is a particular focus of these efforts. Data on AMU in pig production in Ireland are lacking. This study aimed to quantify AMU on Irish pig farms, to identify the major patterns of use employed and to compare the results obtained to those from other published reports and studies.ResultsAntimicrobial use data for 2016 was collected from 67 Irish pig farms which represented c. 35% of national production. The combined sample population consumed 14.5 t of antimicrobial by weight of active ingredient suggesting that the pig sector accounted for approximately 40% of veterinary AMU in Ireland in 2016. At farm level, median AMU measured in milligram per population correction unit (mg/PCU) was 93.9 (range: 1.0–1196.0). When measured in terms of treatment incidence (TI200), median AMU was 15.4 (range: 0.2–169.2). Oral treatments accounted for 97.5% of all AMU by weight of active ingredient and were primarily administered via medicated feed to pigs in the post weaning stages of production. AMU in Irish pig production in 2016 was higher than results obtained from the national reports of Sweden, Denmark, the Netherlands and France but lower than the United Kingdom.ConclusionsPig production in Ireland is an important consumer of veterinary antimicrobials. The quantities and patterns of AMU on Irish pig farms are comparable to pig production in other European countries but higher than some countries with more advanced AMU reduction strategies. This AMU is characterised by a high proportion of prophylactic use and is primarily administered to pigs post weaning via medicated feed. Further studies to better understand the reasons for AMU on Irish pig farms and strategies to improve health among weaner pigs will be of benefit in the effort to reduce AMU.

Effects of spray‐dried animal plasma on the growth performance of weaned piglets—A review

Spray-dried animal plasma sourced from bovine, porcine or other animal origin is often used as a main feed ingredient in the diets of weanling piglets to improve growth performance. The objective of this study was to determine the effect of animal plasma in diets on the performance of piglets in the post-weaning period, with and/or without pathogenic challenge, by undertaking a meta-analysis. Data were extracted from peer-reviewed reports published in scientific journals. The average initial weight of the piglets was 5.8kg and the average initial age 19days (2-56days). The average duration of feeding animal plasma was 40days. Average daily gain (ADG), feed intake (ADFI) and feed conversion ratio (FCR) were found to be 22-28g/day, 20-27g/day and -0.28 to 0.06g/g. Generally, diet supplemented with spray-dried bovine plasma (SDBP) improved the ADG of the piglets and spray-dried porcine plasma (SDPP) led to increases in the ADFI. For the first week post-weaning alone, as the dietary animal plasma percentage increased there was an increase in ADG and ADFI; similarly, the latter two measures increased as weaning age increased. The evidence suggests that mainly IgG present in animal plasma prevents the binding of pathogens to the gut wall and reduces the incidence of sub-clinical infection in the post-weaning stage. Animal plasma containing IgG appears to be a useful in-feed supplement for piglets in the post-weaning phase.

Food groups consumed by Saudi Children during the poste weaning to ‎preschool years, Jeddah, Saudi Arabia ‎‏ ‏

Abstract:‎ Purpose: healthy eating during early childhoods is important for growth and development. We ‎investigated the types of food groups’ consumption among preschool children. Household interview ‎of the mothers were done to indicate the general features of children food consumption and its ‎related strength and weakness.‎ Methods: Between 2017 and 2019 mother of children aged from 2 to 6 year old were interviewed. The ‎sample was cross sectional convenience sample of n=550. The data gathered describes the children’s ‎food intake and environment factors occurring during the children meals.‎ Results: children aged 2 years were repeatedly offered per day 2.6 of the milk group, 2.2 of the grain, ‎‎2.3 of the fruits, 1.5 of the proteins, 1.2 of the vegetables. An increase in the number of repeated ‎offering of the food groups especially milk and snack high in fat and sugar occurs by the preschool ‎stage. Consumption of food high In fat and sugar starts at the post weaning stage and is offered 1.19 ‎per day and increases to 2.03 per day at the preschool stage. The effect of child gender and maternal ‎education on food intake shows mostly no significance at our present sample size.‎ Discussion: Food uptakes of the milk and grains group were the larger and reached up to 3 times daily. ‎Nutrient intense food such as vegetables, fruits, and protein uptake was around one time per day. ‎And calories intense foods high in fat and sugar the up take starts form the earlier age and increased as ‎the children grow. Our study indicate that 80% of mothers prepared fresh food for the child ‎meals and 60% were present in those meals

Prediction of serum biochemistry of pigs at pre- and post-weaning stages of growth using regression tree methods

This study was aimed at evaluating the effects of breed, sex and their interactions on aspects of haematology, serum biochemistry and morphometry of healthy pigs at pre- and post-weaning stages of growth (4 and 12 weeks respectively). It was also aimed at predicting the serum biochemical parameters (SBP) that are biomarkers for growth using regression tree method (RTM). Seventy-one crossbred (71 CB) pigs (Landrace × Local pigs) and 21 Local (L) pigs were reared from birth to adult stage, with blood samples and morphometric parameters (MP) taken at pre- and post-weaning stages. The CB pigs had higher values for aspartate transaminase (AST) (serum glutamic oxaloacetic transaminase, SGOT) (P < 0.05) than local ones, while the female animals had higher values (P < 0.05) than the males at pre-weaning stage of growth. At post-weaning stage, the CB breeds also had higher AST (SGOT) values (P < 0.05) than the L breeds, while among the sexes, the males had higher values for WBC, L, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration (P < 0.05) than the female pigs, but the females were higher for N and AST SGOT (P < 0.05) than the males respectively. However, the prediction of SBP using Exhaustive CHAID algorithm of RTM returned 100% prediction in terms of a single terminal node from all the morphometric parameters at both stages of growth. The terminal nodes of the RTM produced mean values of 34.57 UI/L for alkaline phosphate, 29.25 UI/L for AST and 60.27 UI/L for alanine transaminase (ALT) respectively. This implies that the prediction of ALKPOS, AST (SGOT) and ALT (serum glutamic pyruvic transaminase) using the 5 morphometric traits measured is not significant as no single node was linked to them. Although the node values reported for them are within the range of 0–40 IU/L for healthy pigs, the values for ALT are above this range. Therefore, individual contributions from the morphometric traits could not predict any SBP as the model returned zero node.

Co-modulation of Liver Genes and Intestinal Microbiome of Largemouth Bass Larvae (Micropterus salmoides) During Weaning.

In recent years, largemouth bass have become one of the most commonly aquacultured species in China, however, its low survival rate during larval weaning has always been a bottleneck that has restricted industrial development. Understanding the changes in liver metabolism and intestinal microflora during the weaning of largemouth bass larvae can help to design better weaning strategies and improve survival. In this study, liver mRNA and intestinal microflora 16S rRNA genes were analyzed using high-throughput sequencing at the pre, mid, and post weaning stages [15, 30, 45 days post hatching; total length (cm) were 2.21 ± 0.12, 3.45 ± 0.21, 5.29 ± 0.33, respectively]. The transcriptome results revealed that the genes with increased expression were related to amino acid metabolism in the pre-weaning stage, but they were related to fatty acid metabolism in the post-weaning stage. A similar phenomenon was observed in the intestinal microflora where the dominant microbe Proteobacteria (relative abundance 56.32%) in the pre-weaning stage was gradually replaced by Firmicutes (relative abundance 62.81%) by the post-weaning stage. In addition, the three most important digestive enzymes (trypsin, lipase, and amylase) in the intestine were significantly decreased during the mid-weaning stage (P < 0.05), which was also true for some genes crucial to immune pathways in the liver. Overall, these findings showed that weaning in largemouth bass can cause changes in liver metabolism and intestinal microbial communities, which has improved our understanding of fish adaptation to changes in food sources during weaning.

Investigation of Pre- and Post-Weaning Mortalities in Rabbits Bred in Egypt, with Reference to Parasitic and Bacterial Causes.

Simple SummaryPre- and postweaning stages are critical in the management of rabbits due to the increased risk of mortalities. Mortality rates during pre- and postweaning periods were 67.10% and 31.90%, respectively. The preweaning mortality was mainly due to causes related to does (95.23%) and infectious agents, including Escherichia coli, and Salmonella (4.77%). The postweaning mortality was mainly referred to managemental factors and infectious causes, including Eimeria species, E. coli, and Salmonella. This study was conducted to investigate the causes of mortality in young rabbits. A total of 110 V-Line breed female rabbits aged 5 m were used in this study. Rabbit kits were examined daily in pre- and postweaning stages to detect clinical disorders that caused death. The postmortem examination was carried out on dead kits. Furthermore, rabbits were examined for the probable bacteriological and parasitological causes of death. Fecal samples were collected from each dead kit and examined by standard microbiological procedures for bacterial pathogens and macroscopically and microscopically for the presence of endo- and ectoparasites. Throughout two breeding seasons, 2238 newborns were obtained, of which 1736 died, accounting for a 77.57% mortality rate. During preweaning (1st month of age) and postweaning (up to 3 months of age), 1501 (67.10%) and 235 (31.90%) deaths were recorded, respectively. A postweaning fecal examination revealed that 198 out of 229 (86.50%) were diarrheic rabbits due to Eimeria infection. Cittotaenia spp. eggs were detected in 4.37% of fecal samples, and mites (Sarcoptis scabiei) were present in 6.55%. E. coli was detected in 100% of examined animals during pre- and postweaning periods; however, Salmonella spp. were 97.22% and 43.67, respectively. Managemental risk factors were the main causes in preweaning mortality, including insufficient milk supply (37.37%), cannibalism (26.38%), mange infestation of a rabbit doe (22.20%), mastitis (4.30%), lack of doe care (5.00%), bronchopneumonia (2.13%), and enteritis (1.80%). However, risk factors in postweaning mortality included sudden death with general septicemia (13.80%), enteritis (9.63%), bronchopneumonia (5.43%), mange infestation (2.04%), and malnutrition (0.81%). In conclusion, the etiology of preweaning mortality in kits was related mainly to the doe, especially managemental risk factors. However, a combination of multiple pathogenic agents (parasites and bacteria) and managemental factors was reported in the postweaning stage. Careful attention must be paid to avoid these causes.

Genetic parameter estimates for growth performance of crossbred piglets

The direct heritability estimates for piglet weights in pre and post weaning stages were moderate and improvement through mass selection is plausible. In the pre-weaning stage, the piglets had maximum genetic potential at birth (BW) to be exploited through direct selection. The 3 random effects, namely direct additive, maternal additive and litter permanent environmental effects had significant roles during different phases of pre-weaning growth and all must be included in the model used for formulating a breeding program. For post-weaning traits, the direct additive and permanent litter effects were the predominant factors governing the variability. The non-significance of postweaning maternal influence was as per expectation because the piglets moved away from maternal care after 8thweekof age.

Continuous exposure to α-glycosyl isoquercitrin from developmental stages to adulthood is necessary for facilitating fear extinction learning in rats.

We previously reported that exposure to α-glycosyl isoquercitrin (AGIQ) from the fetal stage to adulthood facilitated fear extinction learning in rats. The present study investigated the specific AGIQ exposure period sufficient for inducing this behavioral effect. Rats were dietarily exposed to 0.5% AGIQ from the postweaning stage to adulthood (PW-AGIQ), the fetal stage to postweaning stage (DEV-AGIQ), or the fetal stage to adulthood (WP-AGIQ). Fear memory, anxiety-like behavior, and object recognition memory were assessed during adulthood. Fear extinction learning was exclusively facilitated in the WP-AGIQ rats. Synaptic plasticity-related genes showed a similar pattern of constitutive expression changes in the hippocampal dentate gyrus and prelimbic medial prefrontal cortex (mPFC) between the DEV-AGIQ and WP-AGIQ rats. However, WP-AGIQ rats revealed more genes constitutively upregulated in the infralimbic mPFC and amygdala than DEV-AGIQ rats, as well as FOS-immunoreactive(+) neurons constitutively increased in the infralimbic cortex. Ninety minutes after the last fear extinction trial, many synaptic plasticity-related genes (encoding Ephs/Ephrins, glutamate receptors/transporters, and immediate-early gene proteins and their regulator, extracellular signal-regulated kinase 2 [ERK2]) were upregulated in the dentate gyrus and amygdala in WP-AGIQ rats. Additionally, WP-AGIQ rats exhibited increased phosphorylated ERK1/2+ neurons in both the prelimbic and infralimbic cortices. These results suggest that AGIQ exposure from the fetal stage to adulthood is necessary for facilitating fear extinction learning. Furthermore, constitutive and learning-dependent upregulation of synaptic plasticity-related genes/molecules may be differentially involved in brain regions that regulate fear memory. Thus, new learning-related neural circuits for facilitating fear extinction can be established in the mPFC.

Estimation of genetic parameters and breeding values for growth traits using random regression model in Landrace × desi crossbred pigs

The experiment was conducted to estimate genetic parameters and breeding value of pre-weaning and postweaning growth traits in Landrace × Desi (indigenous) crossbred pigs. Random regression model (RRM) with fixed effects, random effects of direct additive, maternal genetic, maternal permanent environmental and individual permanent environmental effects and a heterogeneous residual variance structure over growth measurement at different time point was applied to estimate the genetic parameters. Among different order of Legendre polynomial fitted, RRM with heterogeneous error variance (RRM–HET) with fourth order fit for direct genetic, maternal genetic and maternal permanent environmental effect and third order fit for individual permanent environmental effect was found as the best model. The direct genetic heritability estimates were 0.299±0.021 at birth, which was low (0.011±0.006) at W12 and high at W36 (0.582±0.03). The first eigenvalue accounted for more than 98% variation in body weight and the corresponding trajectories had positive values displaying almost linear pattern till weaning and then increased rapidly in post weaning age. This showed that the selection of pigs on the basis of mean body weight at early age can also result in higher body weight in post-weaning stages. The average breeding value for the birth weight, W8 and W32 was 0.951 kg, 10.162 kg and 49.598 kg, respectively. The 42.86% of sire population at W12 and 56.76% at W24 had breeding value higher than the population's mean breeding value indicating existence of genetic variation and thus the scope for increasing the selection pressure.

Economic evaluation of post-weaning and finishing cattle supplemented on pasture

The objective of this study was to evaluate the economic viability, through different supplementation strategies, of the post-weaning and finishing stages of cattle supplemented on Brachiaria brizantha cv. Marandu pastures during the rainy and dry seasons. The experimental period was 447 d. The study comprised the post-weaning and finishing stages of 22 intact male crossbred (½ Holstein-Zebu) cattle with an average initial weight of 164.09 ± 12.13 kg and an average age of 7 mo. The animals were distributed in a randomized design with 11 replications per treatment. The following supplementation strategies were tested: strategy 1 (S1): Mineral mix in the 1st and 3rd periods and protein-energy supplementation at 0.2 % of the body weight (BW) in the 2nd period; and strategy 2 (S2): protein-energy supplementation at 0.4 % BW in the 1st and 3rd periods, and protein-energy supplementation at 0.6 % BW in the 2nd period. Strategy 1 resulted in a lower cost per arroba produced and lower cost per hectare, generating a greater net profit per hectare and consequently a higher internal rate of return. When herbage is available, mineral supplementation supplied during the rainy season, associated with low levels of protein-energy supplementation in the dry season (S1), is of greater economic attractiveness for the development of the project, as it leads to higher internal rates of return and net present values in the entire period.