Automated feeding of sheep. 2. Feeding behaviour influences the methane emissions of sheep offered restricted diets

Context During the non-growing season of pastures and during droughts, the dry-matter intake (DMI) of sheep is often constrained due to low pasture availability and the need to feed for weight loss or maintenance. Below-maintenance feeding may have consequences for methane (CH4) production and yield in farm systems. Aims The effect of six restricted feeding levels on CH4 emissions measured using portable accumulation chambers (PACs) was examined in relation to DMI, oxygen consumption (O2) and carbon dioxide (CO2) emissions and observed changes in feeding behaviour in sheep fed with automated feeders. Methods An automated feeding system was used to apply daily feeding levels to Maternal Composite ewes (n=126). Sheep were adapted to the automated feeding system over 19days, with unlimited access to feed. Following adaptation, sheep were allocated to restricted daily feed levels at 40%, 80%, 100%, 140% and 180% of estimated maintenance requirements (MR) for 41days. Methane, CO2 and O2 emissions from ewes were measured using PACs on Days 30 and 31 of the restricted feeding period. Key results Methane production (g/day) increased (P<0.001) with the level of feeding. However, time since the last meal decreased with the level of feeding and was associated with CH4 production. Sheep on lower levels of feeding tended to consume meals earlier in the day and had longer times since their last meal at PAC measurement and lower CH4 production. These two factors explained 58.7% of the variance in CH4 production in an additive linear model. Methane yield (gCH4/kg DMI) decreased as the level of feeding was increased. Conclusions Methane emissions were affected not only by daily DMI, but also time since the last meal. An understanding of the effect of feeding behaviour and time since the last meal should be incorporated into feeding protocols prior to CH4 measurements when PACs are being used to measure CH4 emissions from sheep fed restricted diets. Implications Utilising automated feeders may improve the accuracy of PAC measurements of sheep CH4 emissions fed both ad libitum and restricted feed amounts, by increasing understanding of DMI and feeding behaviour.

A disintegrin and metalloprotease-12 is type I myofiber specific in Bos taurus and Bos indicus cattle

A disintegrin and metalloproteinase-12 (ADAM12) is involved in the regulation of myogenesis and adipogenesis and is of interest as a potential target to manipulate skeletal muscle development and intramuscular fat (IMF) deposition in cattle to increase beef yield and improve meat quality. The longissimus thoracis muscle (LM) and semitendinosus muscle (STM) from 5 Bos taurus (Angus) and 5 Bos indicus (Brahman) cattle were collected for histological and ADAM12 gene and protein expression analysis. Myofiber typing was used to determine if ADAM12 expression patterns related to differences in muscling and IMF deposition, which are influenced by proportions of the different myofiber types. The STM was found to contain a higher proportion of glycolytic myofibers than the LM, which contained a greater proportion of oxidative myofibers (myofiber ratio of glycolytic to more oxidative types in LM and STM of 1.1 and 3.5, respectively; P < 0.05). ADAM12 gene expression, fluorescent immunohistochemical staining for ADAM12, and image analysis found ADAM12 to be greater in the LM (P < 0.05). Regression analysis found a strong, positive relationship for the distribution of ADAM12 against the proportion of type I myofibers (P < 0.05, r(2) = 0.86). These findings suggest ADAM12 is upregulated in muscles with more slow-oxidative myofibres, such as the LM, and is linked to type I myofibers in cattle. ADAM12 may be important in the regulation and maintenance slow myofibers in the LM muscle.

Discovery and trait association of single nucleotide polymorphisms from gene regions of influence on meat tenderness and long-chain omega-3 fatty acid content in Australian lamb

Whole genome association studies in humans have shown a strong relationship between omega-3 levels in plasma and single nucleotide polymorphisms (SNP) located close to genes whose protein products are involved in the biosynthesis of long-chain omega-3 fatty acids. In sheep and other livestock species, the calpain/calpastatin system is the principal influence on natural variation in meat tenderness between animals. Using targeted next generation sequencing, we sequenced the fatty acid desaturase locus (FADS1/2/3), ELOVL2 and SLC26A10 and the calpain/calpastatin (CAPN1/2/3 and CAST) gene loci of 35 industry sires from the Australian flock. A total of 753 SNP were identified and 182 of these SNP were selected for incorporation onto a research SNP panel that represented the genetic variation across the nine genes. A total of 1252 animals were genotyped from the Australian Sheep CRC Information Nucleus Flock for these SNP and the genomic association was calculated for omega-3 fatty acid content and objective meat tenderness in lamb. Six SNP within CAST and CAPN2 showed association with shear force at Day 5 post-mortem at a significance level of P ≤ 0.01. When these were fitted simultaneously in a mixed-model analysis with fixed effects and covariates, three SNP remained significant. These SNP each had an unfavourable effect on shear force of between 1.1 and 1.8 N, with a combined effect of 4.1 N. The frequency of the favourable alleles in the progeny measured indicates that these SNP hold good potential for improving the management of meat tenderness across Merino, Border Leicester and Terminal sire types. No SNP within the FADS1/2/3, ELOVL2 and SLC26A10 gene regions were associated with lamb muscle omega-3 levels. This indicates that genetic variation in the long-chain omega-3 biosynthesis pathway genes analysed here may not be important for omega-3 content in lamb within the Information Nucleus Flock population.

Production, extraction, and purification of human poly(ADP-ribose) polymerase-1 (PARP-1) with high specific activity

Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme involved in a range of activities associated with DNA metabolism and plays a key role in maintaining the integrity of DNA and chromatin structure. As such, this enzyme is likely to provide a useful target when using a rational drug design approach to develop pharmaceutical reagents, including cancer therapeutics. However, there is still a great deal to learn about the mode of action of PARP-1 and therefore efforts are being directed at gaining a better understanding of the relationship between its structure and function. To this end we have developed a rapid and relatively simple approach to producing and purifying PARP-1. Unlike traditional PARP-1 purification protocols, the method described here requires only one chromatography step thus minimizing losses of the enzyme and also avoids the use of a competitive inhibitor-based affinity chromatography step, which is common to several other protocols in the literature. The product of the method described here is high-quality native PARP-1 with a high specific activity and K(m) and V(max) values similar to what is reported by other workers in the field. This protocol is particularly well suited to making PARP-1 in a quantity and of a quality suitable for structure-function studies.

Continuous ambulatory peritoneal dialysis in a program for children with end stage renal disease

Eighteen infants, children, and adolescents were trained in the techniques of continuous ambulatory peritoneal dialysis (CAPD) as a therapy for end stage renal disease (ESRD) at the University of Florida. Fourteen patients successfully continued CAPD 4-24 months, for a total of 193 patient-months. Uremic symptoms were well controlled with blood urea nitrogen concentration (BUN) decreased to between 60 and 80 mg/dl. Parathyroid hormone levels increased but roentgenographic evidence of osteodystrophy improved in most patients. The rate of peritonitis was one episode in 7.7 patient-months. Blood transfusion requirements decreased for patients transferred from in-center hemodialysis to CAPD with no significant decrease in average hematocrits. Caloric intake was adequate and anorexia was usually not a major problem. Children who were evaluated for growth were under 15 years of age, with bone ages less than 12 years, and were using CAPD for longer than 6 months. Their mean growth velocity was 74.7 +/- 20.4% (SD) of the predicted velocity.