Anthelmintic usage on the Reproductive Parameters in Captive reared Agoutis (Dasyprocta leporina) in Trinidad and Tobago, West Indies

The agouti (Dasyprocta leporina) is a rodent that is found in the Neo-tropical region. This animal is hunted for its meat but has recently been reared in captivity as a source of meat protein in rural communities. A 20-month experiment was carried out to evaluate the effect of an anthelmintic on the reproductive performance of the agouti (Dasyprocta leporina) reared in captivity. This experiment was conducted in the humid tropics of Trinidad and Tobago. Sixteen animals (15 females, 1 male) placed in each of the two treatment groups in a completely randomized study design. In treatment 1 (T1) animals were given subcutaneous injections of Endovet Ces® (Ivermectin/Praziquantel) at 0.2 mg/kg every three months. Treatment 2 (T2) was the negative control group where animals were not exposed to an anthelmintic. Reproductive data were collected at parturition which included birth weight, litter weight, litter size and gender of offspring. The results showed that there was no statistical difference (p > 0.05) between the treatment groups with respect to birth weight, litter weight, litter size and gender. However, agoutis that were dewormed had a higher birth weight (220.24 g vs 209.1 g) and litter weight (369.8 g vs 343 g). The same values were obtained for the litter size (1.7 vs 1.7) and animals that were dewormed had a higher female offspring to male offspring (2.41:1 vs 1.11:1). This experiment demonstrated that the use of an anthelmintic strategically in the management of captive reared agoutis had no statistical effect (p > 0.05) on the reproductive parameters. Therefore, these animals can be kept in captive conditions without being dewormed and produce efficiently with proper feeding and housing management.

Correlations of gestational hemoglobin, placental mineral elements and reproductive performances in pregnant sows

Iron status of sows has a great influence on reproductive performance. Iron deficiency reduces reproductive performance and newborn piglet survival rate of sow. The hemoglobin is a potential predictor for iron status of sows and is convenient for rapid detection in pig farms. However, the relationship between iron status, hemoglobin, placental trace elements and reproductive performance remains unclear. In this study, the hemoglobin and reproductive performance of more than 500 sows with 1 st to 6 th parities at different gestation stages (25, 55, 75, 95, 110 days of gestation) in two large-scale sow farms were collected, and content of placental Fe, Zn, Mn and Cu was analyzed. The results show hemoglobin of sows during pregnancy (d 75, d 95, d 110) decreased significantly (P < 0.001). As the parity increases, the hemoglobin levels of sows at d 25, d 55 of gestation and placental mineral element contents included Fe, Zn, Mn and Cu at delivery decreased (P < 0.05), while the litter size, birth alive and litter weights increased gradually (P < 0.001). Furthermore, hemoglobin during pregnancy had a negative linear correlation with litter weight and average weight (P < 0.05), higher hemoglobin at d 25 of gestation may reduce the number of stillbirths (P = 0.05), but higher hemoglobin at d 110 of gestation was tend to be benefit for the birth (P = 0.01). And there was a significant positive linear correlation between hemoglobin at d 110 of gestation and placental Fe and Mn levels (P = 0.002, P = 0.013). There was also a significant positive linear correlation among Fe, Zn, Mn and Cu in the placenta (P < 0.001). The levels of Fe, Zn, and Mn in placental at delivery were positive related to the average weight of the fetus (P = 0.048, P = 0.027, P = 0.047), and placental Cu was linearly correlated with litter size (P = 0.029). Our research revealed the requirements for iron during gestation were varied in different gestation periods and parities. The feeds should be adjusted according to the gestation periods, parities or iron status to meet the iron requirements of sows and fetal pigs.

Does Nursing Behaviour of Sows in Loose-Housing Pens Differ from That of Sows in Farrowing Pens with Crates?

Sows confined to farrowing crates are restricted in performing natural behaviour such as maternal behaviour. Loose-housing farrowing pens (LH) and farrowing pens with crates (FC) were compared regarding sows’ nursing behaviour via video analyses over four weeks per batch (one day per week). Nursing frequency was similar in LH and FC pens (1.25 ± 0.82 vs. 1.19 ± 0.75 nursings/sow/hour; p > 0.05). However, nursing duration differed between the two systems (LH: 5.7 ± 4.6 min vs. FC: 7.0 ± 5.0 min; odds ratio (OR) 1.168, p = 0.011). In LH pens, more nursing bouts were sow-terminated than in FC pens (OR 0.427, p = 0.001). The probability of sow-terminated nursing occurring increased from week 1 to week 4 (OR 3.479, adjusted p (padj) < 0.001), while that of observing unnursed piglets decreased from week 1 to week 4 (OR 0.301, padj < 0.001) and rose with increasing litter size (OR 1.174, p = 0.010). We conclude that nursing behaviour was affected by the farrowing system, with shorter nursing duration and more nursing terminations by the sow in LH than in FC pens. Since this corresponds to the nursing behaviour of sows in semi-natural conditions, it can be assumed that sows in LH pens are more likely to exhibit natural nursing behaviour.

Effect of mangosteen peel extract on BPA-exposed murine during gestation

Aim: To evaluate the potential protective effects of mangosteen peel extract against BPA-induced abnormalities on-pregnant mice fetus at implantation stage and offspring at post-parturition. Methodology: Pregnant mice were orally administered with BPA (100mg kg-1 b.wt.) and mangosteen peel extract (200mg kg-1 b.wt.) for 16 days. In order to evaluate the effect of MPE treatment on fetus at implantation stage, the pregnant mice were euthanized at day 18 and the fetus number and morphology were examined. Another group of treated dams, were allowed to undergo parturition for evaluating the of maternal weight, litter size and offspring sex-skewness. Results: Upon feeding Mangosteen peel extract (MPE), the average daily weight gain of dams were not significantly different from the control and BPA treated dams. The fetus derived from BPA treated dams were detected with abnormalities such as under development, haemorrhage and absence of vein, whereas fetus from dam treated with MPE and BPA as well as control were normal. The average litter size of all the treatment groups were not significantly different from the control group. BPA treated mice had lower pups survival up to 6 weeks compared to the groups treated with MPE and control. Test of proportion analysis showed BPA-treated group had significantly higher fraction female ratio. Interpretation: BPA is known as endocrine disruptor causing oxidative stress to female reproductive system, hence mangosteen peel extract contains antioxidant substances that have the potential to ameliorate the adverse effects of BPA exposure on dams during pregnancy and its fetus development.

Evaluation of the phenotypic and genomic background of variability based on litter size of Large White pigs

Background The genetic background of trait variability has captured the interest of ecologists and animal breeders because the genes that control it could be involved in buffering various environmental effects. Phenotypic variability of a given trait can be assessed by studying the heterogeneity of the residual variance, and the quantitative trait loci (QTL) that are involved in the control of this variability are described as variance QTL (vQTL). This study focuses on litter size (total number born, TNB) and its variability in a Large White pig population. The variability of TNB was evaluated either using a simple method, i.e. analysis of the log-transformed variance of residuals (LnVar), or the more complex double hierarchical generalized linear model (DHGLM). We also performed a single-SNP (single nucleotide polymorphism) genome-wide association study (GWAS). To our knowledge, this is only the second study that reports vQTL for litter size in pigs and the first one that shows GWAS results when using two methods to evaluate variability of TNB: LnVar and DHGLM. Results Based on LnVar, three candidate vQTL regions were detected, on Sus scrofa chromosomes (SSC) 1, 7, and 18, which comprised 18 SNPs. Based on the DHGLM, three candidate vQTL regions were detected, i.e. two on SSC7 and one on SSC11, which comprised 32 SNPs. Only one candidate vQTL region overlapped between the two methods, on SSC7, which also contained the most significant SNP. Within this vQTL region, two candidate genes were identified, ADGRF1, which is involved in neurodevelopment of the brain, and ADGRF5, which is involved in the function of the respiratory system and in vascularization. The correlation between estimated breeding values based on the two methods was 0.86. Three-fold cross-validation indicated that DHGLM yielded EBV that were much more accurate and had better prediction of missing observations than LnVar. Conclusions The results indicated that the LnVar and DHGLM methods resulted in genetically different traits. Based on their validation, we recommend the use of DHGLM over the simpler method of log-transformed variance of residuals. These conclusions can be useful for future studies on the evaluation of the variability of any trait in any species.

Effects of Litter Size and Parity on Farrowing Duration of Landrace × Yorkshire Sows

Litter size has increased and farrowing duration has also prolonged in recent years. The aim of this study was to analyze the effect of litter size and parity on farrowing duration (FAR) to estimate the possibility of selecting a short farrowing duration. We recorded 32,200 parturitions of 8420 Landrace × Yorkshire sows, determined farrowing duration, litter size, parity, gestation length. Results showed that total number of born (TNB) and parity obeyed a cubic (p = 0.0004, p = 0.004) relationship while number born alive (NBA) and number born dead (NBD) obeyed a linear (p = 0.0239, p = 0.0035) relationship with FAR. Gestation length obeyed a linear (p = 0.02) relationship with FAR. FAR of sows with stillbirth was longer than that of sows without stillbirth. Stillbirth rate increased rapidly from about 2% to 4%, especially when FAR was over 240 min. FAR gradually prolonged with the parities. FAR of 7th parity sows was longer than that of 1st~6th parity sows (p < 0.05), but different parity sows had little difference in the same FAR interval except for gilts. Results indicated it was possible and necessary to consider FAR into pig breeding without worrying about decreasing of live litter size or negative effect of parity if FAR was shorter than 300 min.

A Study on Morphological Growth and Development of Swiss Albino Mice, Wistar Rat and Dunkin Hartley Guinea Pigs

Background: Baseline information on the morphological development of laboratory animals is very scanty. Hence the present study was undertaken to understand the morphological development of experimental animals. Methods: An experiment was conducted at Biogen animal facility, Bangalore in the year 2018 to study the morphological changes with regard to growth and developmental parameters in Swiss albino mice and Wistar rats and body weight in guinea pigs. Ten Swiss albino mice and Wistar rats in advanced pregnancy of similar age groups and comparable litter sizes in the previous kindlings were selected for the experiment, where as five guinea pigs males and females each were selected with same age group. During the study period, litter weight and size at birth and at weaning, time of initiation and completion (full growth of hair) of hair growth, time of opening of eyes and ears recorded in Swiss albino mice and Wistar rats whereas body weight at birth, 3rd day, 6th day, 9th day, 12th day and 15th were recorded in Dunkin Hartley guinea pigs. Result: The results of Swiss albino mice indicated that the average litter weight (grams) and litter size at birth ranged from 1.39 and 7.50 respectively. The average time taken from initiation and full growth of hair covering on body was 7.50 to 15.30 days. Eyes and ears opened at 7.90 and 8.20 days respectively. Average weight of male and female recorded at weaning (25 days) 19.38 and 15.12 respectively and the litter size at the weaning was 9.70 whereas, livability percent was recorded 87.81 at the end of the trial. The results of Wistar rats indicated that the average litter weight (grams) and litter size at birth ranged from 5.07 and 11 respectively. The average time taken from initiation to full growth of hair covering on body was 9 to 16.20 days. Eyes and ears opened at 12.20 days, average weight (grams) of male and female recorded at weaning (25 days) 78.03 and 63.09 respectively. The litter size at the weaning was 9.70. The livability percent was recorded 88.02 at the end of the trial. The results of Dunkin Hartley guinea pigs indicated that the average body weight (grams) of female at birth, 3rd day, 6th day, 9th day, 12th day, 15th (Weaning period) ranged from 94.88, 109.34, 123.94, 139.74, 152.14 and 166.66, respectively. On the other hand, average body weight (grams) of male at birth, 3rd day, 6th day, 9th day, 12th day, 15th (Weaning period) ranged from 145.38, 155.42, 170.50, 185.54, 200.64 and 215.7, respectively.

Genetic factors of functional traits

Selection of functional traits is a challenge for researchers, but an increasingly necessary objective due to the growing concern regarding animal welfare and overcoming the problems of reducing antibiotic use in rabbit production without undermining the animals’ productivity. The aim of this review is to discuss the genetic control of resistance to diseases, longevity and variability of birth weight within a litter, or litter size variability at birth within doe, describing the selection programmes and the first results from a multi-omics analysis of resistance/susceptibility to diseases. The heritability is around 0.13 for longevity, 0.01 for uniformity in birth weight, 0.09 for litter size variability and around 0.11 for disease resistance. Genetic correlations between functional traits and production traits are mostly no different from zero, or are moderately favourable in some cases. Six selection programmes developed in three countries are reviewed. Line foundation with high pressure for selection or divergent selection experiments are different methodologies used, and favourable responses to selection have been achieved. Genomics studies have revealed associations in regions related to immune system functionality and stress in lines selected for litter size variability. Knowledge of the role of gut microbiota in the rabbit’s immune response is very limited. A multi-omics approach can help determine the microbial mechanisms in regulation immunity genes of the host.