Minimising variability in carcass quality to better meet market specifications is a priority for Australian pig producers, however issues with variability in carcass fat distribution have recently been raised, particularly in the belly primal. There has been a rapid increase in the use of low-cost, deep-litter (DL) housing systems in Australia over the past 15 years for rearing pigs. The inherent differences between the physical, thermal, and social environments of conventional (C) and DL production systems may well alter the growth path of the pig and subsequently alter fat metabolism and hence fat deposition and distribution. The general industry view is that pigs finished in DL housing are fatter and grow less efficiently than pigs finished in C housing, however contrasting carcass and growth performance results have been reported between housing systems. It is likely that the different housing environments affect the maintenance energy requirements of the growing pig, thereby affecting the availability of substrates for fat deposition and/or the requirements for fat mobilisation. Hence, raising pigs in C and/or DL production systems was identified as a likely contributor to variability in carcass fat distribution via the effects of the disparate environments on fat metabolism. The overall purpose of this thesis was to establish the effect of keeping pigs in C and/or DL housing systems on fat metabolism, and therefore fat deposition in the growing pig and fat distribution in the finished carcass. Industry considers that finishing pigs in C facilities allows greater flexibility in feeding and marketing decisions, allowing growth efficiency and backfat to be managed more effectively than in a DL system. Therefore an aspect of this thesis was to also examine the effects of an alternative management strategy, raising pigs in a combination of DL and C housing, on growth performance and fat deposition and distribution in the carcass. The presence of straw bedding is a major difference between C and DL housing systems. This was identified as a probable contributor to the differences in growth performance and carcass fat distribution found between pigs raised in the different housing systems, via its thermal properties and/or the ingestion of the straw on pig growth. Experiment 1a and 1b were designed to test the hypothesis that the growth path differs for pigs raised in C and DL housing systems, affecting biochemical indicators of fat metabolism and therefore fat accretion and distribution in the carcass. The study was conducted as a serial slaughter of pigs housed in C and DL systems allowing the pattern of fat accretion, and therefore the distribution of fat in the carcass, to be determined from 15¨C185 kg live weight (LW). The results confirmed the hypothesis that the growth path, fat accretion and fat distribution in the carcass differed for pigs raised in C and DL housing systems. In Experiment 1a, elevated lipogenic enzyme activities, higher percentages of saturated fatty acids (SFA) and higher concentrations of plasma glucose and lactate indicated lipogenesis was elevated in C pigs to 13 weeks of age, compared to young DL pigs, suggesting that fat accretion was higher in young C pigs. At 24 weeks of age however there was a shift in lipogenic enzyme activities, the percentage of SFA in backfat and the concentration of plasma glucose were higher in DL-housed pigs than C-housed pigs, indicating higher rates of lipogenesis. Elevated concentrations of plasma non-esterified fatty acids (NEFA) and glycerol in DL pigs indicated that lipolysis, or fat mobilisation, was higher in DL-housed pigs for the entire growth period. The results from Experiment 1b clearly indicated that during early growth, C pigs grew faster than DL pigs (0.71 vs 0.66 kg/day, P¡Ü0.05) and were heavier between 8-23 weeks of age (P¡Ü0.05). Therefore in conjunction with the results of Experiment 1a, it was expected that young C pigs would be fatter than DL pigs of the same age. However, dissection indicated no treatment differences in total carcass composition, although there was an effect of housing on carcass fat distribution with a trend (P=0.087) for a lower ratio of fat:lean in the belly primal of DL pigs compared to C pigs at 13 weeks of age. After 20 weeks of age however, growth rates were similar for pigs in both housing treatments and by 26 weeks of age there were no treatment differences in live weight (LW) but the rate of fat accretion in DL pigs, particularly in the loin and belly primals, increased rapidly. Differences in the thermal environments of C and DL housing, and therefore differences in the energy demand for thermoregulation, were likely to have contributed to the differences measured in lipogenesis, growth performance and carcass fat distribution. Experiment 2a and 2b tested the hypothesis that moving pigs from DL to C housing for finishing would improve overall growth performance and reduce carcass fatness compared to pigs raised in wean-to-finish DL housing. The biochemical measurements indicated few differences in the rate of lipogenesis between 13-week-old C and DL pigs. However, and in agreement with the findings from Experiment 1a, elevated plasma NEFA concentrations in DL pigs suggested higher rates of lipolysis. Up to 13 weeks of age, pigs in the DL housing system grew faster than C pigs, however similar to the findings of Experiment 1b, DL pigs were less efficient. In addition, P2 backfat depth was less in DL pigs, indicating they were leaner than C pigs, and though not reflected in total carcass composition, again there was an effect of housing on fat distribution. The move to an unfamiliar housing environment affected growth performance, reduced enzyme activity in backfat and the ratio of SFA in belly fat, suggesting these pigs had lower rates of lipogenesis. However in contrast to Experiment 1a, where lipogenesis was higher in older DL pigs compared to older C pigs, pigs finished in the DL housing had a trend for lower enzyme activity in belly fat (P=0.063), suggesting lower rates of lipogenesis, and higher plasma glycerol concentrations, suggesting a higher level of lipolysis compared to C-finished pigs. The carcass composition data (Experiment 2b) found that though there were no differences indicated by differences in P2 depth, there was a strong trend (P=0.057) for DL-finished pigs to have 2-6% less fat in the carcass as a result of significantly less fat in the shoulder (15% vs 17%) and belly (29% vs 33%) primals compared to C-finished pigs. The difference in belly primal composition was a reflection of the lower enzyme activities in belly fat and higher plasma glycerol concentrations in DL finished pigs. The results suggest that the type of housing during the finishing growth period has a greater impact on fat accretion and carcass composition than the type of housing during the grower period, or changing housing environment during growth. However, changing housing environment at 13 weeks of age affected growth, where there was a temporary reduction in daily LW gain, and therefore significantly lower (P¡Ü0.001) LW at slaughter (117 kg LW), compared to pigs that had remained in C or DL housing from wean-to-finish (123 kg LW). Moving pigs from DL to C housing to control carcass fat and improve growth performance compared to pigs grown wean-to-finish in DL housing, was not successful, and had a negative impact on performance and carcass quality by reducing growth efficiency and LW and increasing carcass fatness. The results also showed that contrary to the industry view that DL raised pigs are fatter, pigs in this experiment finished in DL housing had a lower fat:lean ratio in the carcass than pigs finished in the C system (P¡Ü0.05). The effects of straw on growth performance and carcass composition were evaluated in Experiment 3a and 3b by including straw in the grower and finisher diets (St+) and/or providing straw bedding (Bed+) to C-housed pigs. The experiment tested the hypothesis that the presence of straw alters the growth paths of pigs, affecting fat distribution in the carcass. Straw, as bedding and in the diet, affected pig growth paths and altered carcass fat distribution and, consistent with the findings for DL pigs in Experiments 1b and 2b, there was a trend for pigs with access to straw to have less fat in the belly (P=0.072). Elevated activity of key enzymes involved in lipogenesis, measured in Experiment 3a in belly fat and backfat from pigs fed the St+ diet, and a higher ratio of SFA in belly fat of pigs housed on concrete without straw bedding, suggested that in this experiment straw ingestion increased lipogenesis in belly fat and backfat of the growing pig, whilst straw bedding reduced lipogenesis in belly fat. Experiment 3b demonstrated an additive effect of straw on growth where average LW at slaughter for pigs without access to straw was significantly lower (110 kg), compared to pigs with access to one source of straw either via the diet or bedding (115 and 114 kg LW respectively), and pigs that had two sources of straw available (119 kg LW) (P¡Ü0.05). Although LW differed between treatments there were no differences in total carcass fat (P>0.10), yet there was an effect of straw on fat distribution. Pigs with access to straw had a lower ratio of fat and a higher ratio of lean tissue in the belly primal (P=0.072) compared to pigs that did not have straw. The effect of straw ingestion on lipogenesis and fat deposition may have occurred via the effects of dietary fibre (DF) on the dilution of dietary energy density. Pigs were able to compensate for the energy/nutrient dilution by increasing VFI and therefore growth was not affected, however fat acts as an insulator, and localised differences in fat distribution may have been related to increased heat production (HP) from the digestion of greater volumes of feed. In response, fat deposition may have been directed away from the belly location in order to facilitate heat loss. Floor type may have also affected fat distribution via differences in thermal conductivity. Straw has a lower thermal conductivity than concrete, hence pigs housed on concrete flooring may have a greater requirement for fat in the belly to reduce conductive heat loss. Results from Experiment 3a and 3b provided evidence that pigs housed on bedding consume straw in sufficient quantities. Pigs fed the straw diet had significantly higher concentrations of plasma acetate than pigs fed the control diet (P¡Ü0.001), and there was a trend for pigs housed on straw bedding to have higher levels than pigs without access to straw. An increase in plasma acetate can indicate increased microbial activity in gut, which occurs in response to higher levels of DF. In addition, pigs bedded on straw had higher gastrointestinal tract weights, which can also indicate higher levels of DF intake. Regression analyses of data across experiments showed that P2 backfat depth, the primary carcass composition prediction tool, accounted for less than 50% of the variation in percent carcass fat (R2=0.41). Furthermore, across experiments, P2 accounted for very little of the variability in percent belly fat (R2=0.01). These results highlight the inconsistency of P2 depth as a reliable indicator of carcass composition and the need for the development of additional criteria to be used in the selection of carcasses for specific markets as the composition of the belly primal was not indicated by the current carcass measurement system. From the results obtained in this thesis, it was proposed that: 1) The growth path of pigs is altered by the housing system in which they are reared and the more variable ambient temperature of the DL housing system would increase the energy requirement of young pigs for thermoregulation. As a consequence of the altered growth paths, fat metabolism differs for pigs raised in DL and C production systems. Lower rates of lipogenesis may occur in young DL pigs compared to C pigs and this can change as pigs grow, however fat mobilisation remains higher in DL pigs during growth. 2) Differences in the rate of lipogenesis, indicated by the biochemical measures, were generally not reflected in total carcass composition, however there were differences in carcass fat distribution where pigs raised in DL systems consistently had less fat in the belly primal. Rearing environment may provide an additional criterion when selecting carcasses for specific markets where variability in belly composition is an issue. 3) Pig raised in the DL environment are not always fatter than pigs housed in C facilities, and moving pigs from one housing environment to another during the growing-finishing period disrupts the growth path reducing growth performance and can increase carcass fatness. 4) Straw bedding, via ingestion and via its physical thermal properties, affects pig growth and fat distribution and may explain in-part the differences in pig growth performance and carcass quality found between C and DL housing systems.

Thesis (M.S.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed on Sept. 3, 2009). Includes bibliographical references (p. 50-67).

It has been shown that post-menarcheal girls are more likely to have increased their body weight and body mass index (BMI) than pre-menarcheal girls of the same age. In addition to the metabolic changes which occur during this interval, behavioural risk factors synergize to promote weight gain, putting adolescents at a much higher risk for excess weight gain and its associated health complications. Moreover, obesity during adolescence increase the risk of becoming an obese adult. A systematic review of English and French articles using MEDLINE, EMBASE, Cochrane, and CINAHL was conducted. Studies underwent a three level screening assessment by two independent assessors. Only studies with post-menarcheal weight change information were selected for data extraction and quality assessment, which was conducted by two independent reviewers. A meta-analysis was conducted for weight change and included 389 girls. Five studies discussed the effects of menarche on body weight change. Pooled results for three studies indicated a 10.39 kg increase from pre to post-menarche (95% CI, 9.16-11.62). The other two studies showed significant increases in body fat mass (p<0.05) and higher skinfolds measurements for post-menarcheal girls compared to pre-menarcheal girls. It is important to further explore the bio-psychosocial and environmental factors influencing the weight, especially the total fat mass and body fat distributions in young adolescent girls during the menarche transition in order to develop and evaluate preventive intervention strategies to prevent adolescent and adult obesity.

Elevated risk of cardiometabolic disease is magnified by variation in body fat distribution, in particular increased accumulation of visceral fat. Genome-wide association studies have mainly focused on anthropometric indices such as WHR and BMI to assess adiposity. They successfully identified over 100 loci highlighting for total fat mainly pathways in the brain involved in the regulation of energy expenditure and appetite and for fat distribution genes expressed in adipose and the periphery. Although genetic variants affecting localised fat deposition are known, the functional mechanisms of regional fat accumulation remain poorly understood. Here, we aimed to explore the genetic contribution to body composition to gain further mechanistic insight, and increase our understanding of the role of such genetic variants in metabolic health. We focused on the isolated population of Orkney. 1,301 participants from the Orkney Complex Disease Study, ORCADES underwent DXA scans allowing direct assessment of fat mass in various depots around the body. Genetic data imputed to the 1000 Genomes Project enabled the investigation of 35 million genetic variants. We first used univariate and bivariate analysis to quantify the contribution of genetic factors to the variation of body composition and establish genetic correlations with metabolic traits. We carried out genome-wide association analyses for body composition to identify new underlying genetic loci. We sought to replicate these findings in the Icelandic AGES cohort and the UK Biobank, with 3,219 and 1,575 participants with body composition analysis, respectively. We investigated the coding variation or the regulatory landscape around the associated variants to understand their functional impact. We further focused on one of the associated loci in greater detail. To establish a potential, causal gene for the associated variants and understand the impact of genetic variation on the regulatory elements, we carried out chromatin conformation studies around ENPP6 by. We then explored the role of causal gene candidate on body composition and metabolic health in an animal mouse model. Individual fat depots were moderately heritable with heritability estimates ranging from 35-50% in ORCADES. The genetic correlations with metabolic traits were highest with android, and visceral fat and the ratio of android and gynoid fat percentage: Insulin (0.68-0.75), HOMA-B (0.58-0.70), HOMA-IR (0.69-0.75), CRP (0.47-0.55) and DBP (0.49-0.58). Genome-wide association analysis identified three regions associated with body composition: VRTN, EXOC6B and ENPP6. Low frequency variants on chromosome 4, mapping within the ENPP6 gene associated with the ratio of android and gynoid fat (p= 4.5x10-10), which replicated in abdominal fat by CT in AGES (p=0.003). Per allele, variant carriers show a reduction in android fat by 3% and visceral fat of 140g as well as lowered diastolic blood pressure of 10mmHg. Due to this evidence ENPP6 was chosen as a focus for further mechanistic and functional studies. The lead SNPs map to an ENCODE-predicted DNase1 hypersensitivity site within the second intron of the ENPP6 gene, suggesting a role in genome regulation. Marking the areas with sequence-specific probes by 3D fluorescent in situ hybridisation confirmed that the association interval co-localised more frequently with the ENPP6 promoter than with other gene promoters within the same chromosomal region in SH-SY5Y neurons (p=0.01) but not human SGBS adipocytes. This indicates ENPP6 as a possible causal gene. Consistent with this ENPP6 mRNA levels were extremely low in human subcutaneous and visceral adipose tissue. ENPP6 expression is highest in the brain and kidney, suggesting a neuronal/renal mediated mechanism driving body composition. To model the impact of Enpp6 on adiposity in vivo, Enpp6-/- mice were generated and their metabolic profile investigated. Enpp6-/- mice showed a decrease in visceral fat depot and improved glucose tolerance (n= 24, pfat=0.002, pGTT=0.001). However, no difference was found with regards to their feeding or physical activity behaviour, suggesting an intrinsic alternative to maintaining an energy balance. Using the advantage of genetic drift in a population isolate and direct fat phenotyping we confirmed the contribution of genetic variants to variation in body composition and describe the involvement of three particular loci VRTN, EXOC6B and ENPP6. In particular, we describe ENPP6 as a likely neuronal mechanism underlying selectively visceral adiposity in humans and mice. This study sets a starting point for the investigation into ENPP6 as an anti-obesity and anti-diabetes therapeutic.

Obesity is a growing health problem characterized by a variety of related complications like fatty liver disease, Type 2 diabetes and cardiovascular diseases. One of the major organs relevant for obesity is the adipose tissue (AT) and in the last decades it has been shown that AT is an endocrine organ located in different sites of the body. The AT is mainly distributed in two depots, the subcutaneous adipose tissue (ScAT) and visceral adipose tissue (VAT). It is well acknowledged that fat stored prominently in VAT makes subjects more prone for metabolic complications. It is also known that obesity as well as fat distribution are controlled by genetic factors including single nucleotide polymorphisms, deletions or insertions of nucleotides or sequences; but also the altered mRNA expression or epigenetic modifications like DNA methylation play a role. There is clear evidence that the majority of obesity cases have a polygenic character. This thesis aims to identify and characterize novel candidate ( HIF3A, REPIN1, IRX3/5 and KLF13) genes to gain further insights into different types of obesity and into causes and consequences of adverse FD, including related comorbidities.

Obesity is a growing health problem characterized by a variety of related complications like fatty liver disease, Type 2 diabetes and cardiovascular diseases. One of the major organs relevant for obesity is the adipose tissue (AT) and in the last decades it has been shown that AT is an endocrine organ located in different sites of the body. The AT is mainly distributed in two depots, the subcutaneous adipose tissue (ScAT) and visceral adipose tissue (VAT). It is well acknowledged that fat stored prominently in VAT makes subjects more prone for metabolic complications. It is also known that obesity as well as fat distribution are controlled by genetic factors including single nucleotide polymorphisms, deletions or insertions of nucleotides or sequences; but also the altered mRNA expression or epigenetic modifications like DNA methylation play a role. There is clear evidence that the majority of obesity cases have a polygenic character. This thesis aims to identify and characterize novel candidate ( HIF3A, REPIN1, IRX3/5 and KLF13) genes to gain further insights into different types of obesity and into causes and consequences of adverse FD, including related comorbidities.

Background: Skinfold thickness (ST), waist circumference (WC) and hip circumference (HC) measurements are simple methods for assessing fat tissue at defined body parts. We examined these parameters in a cohort of healthy children and adolescents in Leipzig. Our study provides current percentile curves for biceps, triceps, subscapular and iliac crest ST, plus WC, HC, Waist-to-Hip Ratio and Waist-to-Height Ratio. Materials and methods: 6,344 visits were recorded involving 2,363 individuals from 3 to 16 years in age. Continuous age- and gender-related percentiles (3rd, 10th, median, 90th, 97th percentiles) were estimated using Cole's LMS method. Results: For biceps and triceps ST, boys show a peak at the beginning of adolescence with a subsequent decrease, while percentile values among girls rise across the age range. Subscapular and iliac crest percentiles also show increasing curves with disproportionately high values for P90 and P97. Boys show higher values of WC, girls have higher levels of HC. WC and HC median percentiles constantly increase in both sexes with a plateau at the age of 16 for girls. Conclusion: Trends for all parameters of body fat are in line with other national and international studies. Unlike the KiGGS study, our study provides circumference data across the whole of our age range, i.e. from 3-16 years.:I. Abkürzungsverzeichnis 1. Vorbemerkung 2. Wissenschaftlicher Hintergrund 2.1. Übergewicht und Adipositas im Kindes- und Jugendalter 2.2. Bestimmung des Körperfettanteils bei Kindern und Jugendlichen 2.3. Die Bedeutung kindlichen Übergewichts und dessen Folgeschäden 2.4. Assoziation von Körperfettparametern und kardiovaskulären Risikofaktoren im Fokus 2.5. Anthropometrische Referenzwerte für Kinder und Jugendliche in Deutschland 3. Fragestellung 4. Publikation 5. Zusammenfassung der Arbeit 6. Literaturverzeichnis II. Anlagen 1. Abbildungen 2. Tabellen 3. Formeln nach Slaughter zur Abschätzung des Körperfettanteils III. Darstellung des eigenen Beitrags IV. Erklärung über die eigenständige Abfassung der Arbeit VI. Danksagung

Background and Purpose – The relationship between abdominal body fat and cardiovascular health is not completely understood. This study investigated the association between percent body fat, fat distribution and intima-media thickness (IMT) in healthy middle-aged women. Methods – 224 middle-aged (mean age = 43.1 years ± 3.0), nonsmoking women were included in this study. The women were assessed with a B-mode, high-resolution ultrasonograph to measure the intima-media thickness of the right common carotid artery (CCA). Measurements for percent body fat and fat distribution were assessed using Bod Pod and waist circumference (WC) measured at the umbilicus, respectively.Results – Data were separated into quartiles with the middle two groups combined in order to identify potential differences in IMT based on waist circumference and body fat percent groups. Mean IMT for the entire sample was .569 mm ± .06. Multiple regression with and without control for potential confounding factors yielded insignificant results for all analyses. Conclusions – In the present study, using a sample of healthy middle-aged women, there were no differences in IMT based on overall body fat percent or waist circumference measurements. This finding is somewhat unexpected, however, regional body fat and CCA-IMT have been shown in some, but not all studies to be positively associated with IMT. More research is needed in this area in order to more clearly identify and understand early risk for cardiovascular disease in women.

Body fat distribution has been identified as a more significant risk factor for metabolic-related diseases. This study investigated whether body fat distribution affects dietary outcomes (quality and intake), anthropometric measures, body composition, and skin carotenoid levels. A cross-sectional study with 91 female students was conducted. Thirty-one percent of participants (n=28) had an android body fat distribution. Body fat distribution was associated with WC and WHtR (p

Preferential fat accumulation in visceral vs. subcutaneous depots makes obese individuals more prone to metabolic complications. Body fat distribution (FD) is regulated by genetics. FD patterns vary across ethnic groups independent of obesity. Asians have more and Africans have less visceral fat compared with Europeans. Consequently, Asians tend to be more susceptible to type 2 diabetes even with lower BMIs when compared with Europeans. To date, genome-wide association studies (GWAS) have identified more than 460 loci related to FD traits. However, the majority of these data were generated in European populations. In this review, we aimed to summarize recent advances in FD genetics with a focus on comparisons between European and non-European populations (Asians and Africans). We therefore not only compared FD-related susceptibility loci identified in three ethnicities but also discussed whether known genetic variants might explain the FD pattern heterogeneity across different ancestries. Moreover, we describe several novel candidate genes potentially regulating FD, including NID2, HECTD4 and GNAS, identified in studies with Asian populations. It is of note that in agreement with current knowledge, most of the proposed FD candidate genes found in Asians belong to the group of developmental genes.