Maternal Supplementation with Dietary Betaine during Gestation to Improve Twin Lamb Survival

The effects of maternal calcium status during late gestation on lamb growth and survival in twin-bearing Merino ewes grazing pasture

Our project aimed to investigate whether low maternal calcium status during late gestation decreased weight, growth and survival of lambs born to twin-bearing Merino ewes grazing pasture. On day 130 of gestation, approximately a 10 mL blood sample was collected from 108 twin-bearing Merino ewes. Blood pH and calcium ion concentration were measured in whole blood and serum was analysed for calcium, magnesium, phosphate, beta hydroxy butyrate, non-esterified fatty acids and cholesterol. Six to 18 h after birth and at 49 days of age, lamb live weight was recorded. Ewe serum calcium level at day 130 of gestation were divided into tertiles (1.58-2.13, 2.14-2.30, and 2.31-2.99 mmol/L) with ewes classified as either Low, Med or High (n = 36 per group). A general linear mixed model was used to analyse the data. Survival to 1, 2, 3 and 7 days of age was lower for lambs born to ewes in the Low calcium group compared with those born in the Med and High calcium groups (P < 0.05). At day 49 of age, lamb survival tended to be lower for lambs in the Low (73.6%) compared with Med (86.8%) and High (85.3%) calcium groups (P < 0.1). There were no differences in lamb body weight (P > 0.05). Calcium levels of ewes in the Low calcium group were, on average, indicative of subclinical hypocalcaemia, with this group of ewes also having the lowest lamb survival rate, suggesting that maternal subclinical hypocalcaemia reduces lamb survival. Further studies, particularly on improving maternal calcium levels, are warranted.

Effects of negative dietary cation-anion difference and calcidiol supplementation in transition diets fed to sows on piglet survival, piglet weight, and sow metabolism

Diets that provide a negative dietary anion cation difference (DCAD) and supplement with a vitamin D metabolite 25-OH-D3 (calcidiol) may increase calcium availability at parturition, and enhance piglet survival and performance. This factorial study assessed the effects of DCAD, calcidiol (50 µg/kg), and parity (parity 1 or >1) and their interactions. Large White and Landrace sows (n = 328), parity 1 to 8 were randomly allocated in blocks to treatment diets from day 103 of gestation until day 3 postfarrow: 1) negative DCAD without calcidiol (negative DCAD + no CA), n = 84, 2) negative DCAD with calcidiol (negative DCAD + CA) n = 84, 3) positive DCAD without calcidiol (negative DCAD + no CA), n = 81, and 4) positive DCAD with calcidiol (positive DCAD + CA), n = 79. Negative DCAD diets were acidified with an anionic feed (2 kg/t) and magnesium sulfate (2 kg/t). All treatment diets contained cholecalciferol at 1,000 IU/kg. Dry sow diets contained 14.8% crude protein (CP), 5.4% crude fiber (CF), 0.8% Ca, and 83 mEq/kg DCAD. Treatment diets 1 and 2 contained 17.5% CP, 7.3% CF, 0.8% Ca, and -2 mEq/kg DCAD. Treatment diets 3 and 4 contained 17.4% CP, 7.4% CF, 0.8% Ca, and 68 mEq/kg DCAD. Before farrowing, all negative DCAD sows had lower urine pH than all sows fed a positive DCAD (5.66 ± 0.05 and 6.29 ± 0.05, respectively; P < 0.01); urinary pH was acidified for both DCAD treatments indicating metabolic acidification. The percentage of sows with stillborn piglets was not affected by DCAD, calcidiol, or parity alone but sows fed the negative DCAD + CA diet had a 28% reduction in odds of stillbirth compared to the negative DCAD + no CA diet and even lesser odds to the positive DCAD + CA diet. At day 1 after farrowing, blood gas, and mineral and metabolite concentrations were consistent with feeding a negative DCAD diet and that negative DCAD diets influence energy metabolism, as indicated by increased glucose, cholesterol, and osteocalcin concentrations and reduced nonesterified free fatty acids and 3-hydroxybutyrate concentrations. In the subsequent litter, total piglets born and born alive (14.7 ± 0.3 and 13.8 ± 0.3 piglets, respectively; P = 0.029) was greater for positive DCAD diets compared to negative DCAD diets; and there was an interaction between DCAD, calcidiol, and parity (P = 0.002). Feeding a negative DCAD diet influenced stillbirth, subsequent litter size, and metabolic responses at farrowing. More studies are needed to define optimal diets prefarrowing for sows.

Validation of a handheld refractometer to assess Merino ewe colostrum and transition milk quality

Colostrum quality is generally defined by the IgG concentration in colostrum, and many methods have been used to assess it. Methods to measure colostrum quality both in the laboratory and in the field have been validated in cattle; however, this is only a recent topic of interest for sheep colostrum. Laboratory-based methods are often time consuming and require trained personnel compared with new handheld evaluation tools such as the digital Brix refractometer, which gives real-time results. The aims of this study were to (1) evaluate the relationship between the digital Brix refractometer and constituents indicative of quality (IgG, protein, fat, and lactose) in colostrum and transition milk, and (2) determine an appropriate Brix % cut-off value for the Brix refractometer in sheep colostrum and transition milk. The study used 50 colostrum samples (collected at 0 h postpartum, before lambs' sucking) and 169 transitional milk samples (collected at 4 and 24 h postpartum, after lambs had sucked) collected over 6 lambing trials in 2 years (2019 and 2020). We concluded that the Brix refractometer results correlated weakly with IgG concentration determined by radial immunodiffusion assay in colostrum collected at 0 h postpartum (r = 0.11) and in transition milk collected at 4 h postpartum (r = 0.12); however, a moderate to strong correlation was shown in transition milk samples collected at 24 h (r = 0.66). Brix % was significantly correlated with fat %, lactose %, and protein % at all timepoints. To determine an appropriate Brix % cut-off value indicating an IgG concentration of 20 mg/mL, we analyzed sensitivity and specificity of the Brix refractometer at 0, 4, and 24 h. In samples collected at 0 and 4 h, the highest combination of sensitivity, specificity, and accuracy was achieved at a Brix % cut-off value of 29%; in samples collected at 24 h postpartum, a Brix % cut-off value of 27% gave the highest sensitivity, specificity, and accuracy. Overall, the Brix refractometer has potential as a useful in-field tool for researchers and producers in both extensively and intensively managed flocks to measure and determine the quality of sheep colostrum and transition milk.

Supplementary Tryptophan Fed to Sows Prior to and after Farrowing to Improve Piglet Growth and Survival

Simple Summary

Pre-weaning mortality is a significant economic and welfare issue for the Australian pig industry. Tryptophan can increase serotonin and melatonin production. Serotonin can decrease stress and indirectly increase calcium, which may improve sow health. Meanwhile, melatonin may decrease stillbirths and improve piglet viability at birth and, in turn, increase survival to weaning. This study determined whether feeding 0.16%, 0.42% or 0.56% tryptophan (per kg of feed) to sows during late pregnancy until seven days of lactation could improve piglet survival and viability to weaning and increase the levels of calcium and melatonin in sows. Supplementing tryptophan at levels of 0.42 and 0.56% increased piglet survival compared to no supplementation but did not have an effect on piglet viability. Furthermore, tryptophan supplementation did not increase sow melatonin and calcium levels compared to 0.16%. Further research is required to understand how tryptophan may improve piglet survival, particularly through sow maternal behaviour, and if 5-hydroxytryptophan (the form of tryptophan that directly converts to serotonin and melatonin) would further improve piglet survival.

Abstract

Tryptophan indirectly increases plasma calcium levels, which may improve sow health, and melatonin production, which may improve piglet survival when supplemented during late gestation and lactation. It was hypothesised that tryptophan would increase piglet survival and increase sow circulating melatonin and calcium. Seventy-two multiparous (Landrace x Large White) sows were allocated to either control (0.16% tryptophan; n = 24), low tryptophan (0.42%; n = 24) or high tryptophan (0.56%; n = 24). Piglet viability measures consisted of weights, behaviour, meconium staining, rectal temperature, blood glucose and serum immunoglobulin G concentration. Blood samples collected from sows were analysed for melatonin (two daytime and three night-time samples; n = 17) and calcium (two samples pre- and post-farrowing; n = 14). Both tryptophan treatments increased piglet survival compared to the control group (p < 0.001). Tryptophan had no effect on piglet viability (p > 0.05) and no effect on sow plasma melatonin and calcium concentrations compared with the control group (p > 0.05) except at 21:00 when low tryptophan sows had higher melatonin concentration compared with high tryptophan (p = 0.011). Further research to understand the mediating effects of tryptophan (particularly 5-hydroxytryptophan) on piglet survival, including sow behaviour, is warranted.

Melatonin Regulates Differentiation of Sheep Brown Adipocyte Precursor Cells Via AMP-Activated Protein Kinase

In sheep industry, hypothermia caused by insufficient brown adipose tissue (BAT) deposits is one of the major causes of lamb deaths. Enhancing the formation and function of BAT in neonatal lamb increases thermogenesis and hence reduces economic losses. The aim of the present study was to explore the effect and mechanism of melatonin on sheep brown adipocyte formation and function. Sheep brown adipocyte precursor cells (SBACs) isolated from perirenal BAT were treated with melatonin (1 and 10 nM). The SBACs subjected to melatonin exhibited a decreased proliferation ability, accompanied by down-regulated proliferating cell nuclear antigen, cyclin D1, and CDK4 protein contents in a melatonin dose-dependent manner. Melatonin promoted brown adipocyte formation and induced the expression of brown adipogenic markers, including uncoupling protein 1 and PR domain-containing 16 during differentiation of SBAC. Moreover, the AMP-activated protein kinase α1 (AMPKα1) activity was positively correlated with brown adipocyte formation potential. Importantly, melatonin effectively activated AMPKα1. Furthermore, promotional effects of melatonin were abolished by AMPKα1 knockout, suggesting the involvement of AMPKα1 in this process. Collectively, these results suggested that melatonin enhanced brown adipocyte formation in SBACs in vitro through activation of AMPKα1.

Beneficial Effects of Betaine: A Comprehensive Review

Medicinal herbs and many food ingredients possess favorable biological properties that contribute to their therapeutic activities. One such natural product is betaine, a stable, nontoxic natural substance that is present in animals, plants, and microorganisms. Betaine is also endogenously synthesized through the metabolism of choline or exogenously consumed through dietary intake. Betaine mainly functions as (i) an osmolyte and (ii) a methyl-group donor. This review describes the major physiological effects of betaine in whole-body health and its ability to protect against both liver- as well as non-liver-related diseases and conditions. Betaine's role in preventing/attenuating both alcohol-induced and metabolic-associated liver diseases has been well studied and is extensively reviewed here. Several studies show that betaine protects against the development of alcohol-induced hepatic steatosis, apoptosis, and accumulation of damaged proteins. Additionally, it can significantly prevent/attenuate progressive liver injury by preserving gut integrity and adipose function. The protective effects are primarily associated with the regulation of methionine metabolism through removing homocysteine and maintaining cellular SAM:SAH ratios. Similarly, betaine prevents metabolic-associated fatty liver disease and its progression. In addition, betaine has a neuroprotective role, preserves myocardial function, and prevents pancreatic steatosis. Betaine also attenuates oxidant stress, endoplasmic reticulum stress, inflammation, and cancer development. To conclude, betaine exerts significant therapeutic and biological effects that are potentially beneficial for alleviating a diverse number of human diseases and conditions.

Supplementing pregnant Merino ewes with caffeine to improve neonatal lamb thermoregulation and viability

Percentages of lamb mortalities prior to weaning are a significant and persistent problem for the Australian sheep industry. Maternal caffeine supplementation reduced stillbirths and improved viability in piglets; however, the efficacy of caffeine in enhancing viability and lamb survival is equivocal. The aim of this study was to determine the optimal concentration and duration of maternal caffeine supplementation to improve lamb viability; time to stand and suck with consumption of colostrum occurring, as well as survival to weaning. Multiparous Merino ewes were supplemented with either 0 (CTL), 10 (C10) or 20 mg/kg (C20) body weight (BW) caffeine in feed after day 120 of gestation (dG), or 20 mg/kg BW (LC20) caffeine from dG 142 until parturition. Ewes were housed indoors in individual lambing pens from dG 130 to 72 -h post-partum (pp). Values for pp ewe and lamb variables were analysed using a generalised linear mixed model in IBM SPSS version 25. While ewes within the CTL, C10 and LC20 groups consumed more caffeine compared to C20 ewes (P =  0.001), lambs of C20 ewes had greater rectal temperatures at 20 -h pp (P =  0.021), greater 4 -h serum IgG concentrations (P =  0.041), a longer latency to first sucking bout (P =  0.030), and a greater number of sucking attempts (P =  0.044) compared to lambs from CTL, C10 and LC20 ewes. These results indicate that caffeine supplementation during late-gestation stimulates neonatal lambs as a result of increased sucking (4 -h serum IgG) and increased temperatures within the first 24 -h.