Daniel C. Rule

Maternal Undernutrition from Early- to Mid-Gestation Leads to Growth Retardation, Cardiac Ventricular Hypertrophy, and Increased Liver Weight in the Fetal Sheep

Abstract Early gestation is critical for placentomal growth, differentiation, and vascularization, as well as fetal organogenesis. The fetal origins of adult disease hypothesis proposes that alterations in fetal nutrition and endocrine status result in developmental adaptations that permanently change structure, physiology, and metabolism, thereby predisposing individuals to cardiovascular, metabolic, and endocrine disease in adult life. Multiparous ewes were fed to 50% (nutrient restricted) or 100% (control fed) of total digestible nutrients from Days 28 to 78 of gestation. All ewes were weighed weekly and diets adjusted for individual weight loss or gain. Ewes were killed on Day 78 of gestation and gravid uteri recovered. Fetal body and organ weights were determined, and numbers, morphologies, diameters, and weights of all placentomes were obtained. From Day 28 to Day 78, restricted ewes lost 7.4% of body weight, while control ewes gained 7.5%. Maternal and fetal blood glucose concentrations were reduced in restricted versus control pregnancies. Fetuses were markedly smaller in the restricted group than in the control group. Further, restricted fetuses exhibited greater right- and left-ventricular and liver weights per unit fetal weight than control fetuses. No treatment differences were observed in any gross placentomal measurement. However, caruncular vascularity was enhanced in conceptuses from nutrient-restricted ewes but only in twin pregnancies. While these alterations in fetal/placental development may be beneficial to early fetal survival in the face of a nutrient restriction, their effects later in gestation as well as in postnatal life need further investigation.

Comparison of acidic and alkaline catalysts for preparation of fatty acid methyl esters from ovine muscle with emphasis on conjugated linoleic acid.

Methanolic reagents containing acidic catalysts, HCl (0.5 M, 1 h, 80° C) or BF(3) (14%, 1 h, 80° C), or alkaline catalysts, KOH (0.2 M, 15-60 min, 50° C) or NaOCH(3) (0.5 M, 15-60 min, 50° C), were compared for use in preparation of fatty acid methyl esters for GC analysis of total lipids from freeze-dried semitendinosus muscle of lambs fed a 3.6% linoleate diet. Lipid preparations were in duplicate and included a total lipid extract, as well as direct transesterification and direct saponification of freeze-dried muscle. For the total lipid extracts, the weight% of 18:2 cis-9, trans-11 (CLA) with BF(3) (1.15) was 14.0% lower (P=0.001) than with either KOH (1.32) or NaOCH(3) (1.36); however, with HCl (1.25) CLA was intermediate (P=0.02). Concentrations of CLA (mg/g tissue) were similar (P ⩾0.44) within acidic or alkaline catalysts, but were 18.1% higher (P ⩽0.01) with KOH (2.56) and NaOCH(3) (2.52) than with HCl (2.01) or BF(3) (2.12). For direct transesterification, weight% of CLA was similar (P=0.55) with KOH (1.34) and NaOCH(3) (1.33), but each was 11.9% greater (P=0.003) than with HCl (1.18) and 19.1% greater (P=0.005) than with BF(3) (1.08). Concentrations of CLA after direct transesterification were greatest (P ⩽0.04) with KOH (3.31), followed by HCl (2.89, P=0.04), BF(3) (2.42, P ⩽0.004), and lowest (P ⩽0.002) with NaOCH(3) (2.21), indicating differences in efficiency of direct transesterification. Weight% of CLA in semitendinosus muscle, ranked highest to lowest, was lambs fed 3.6% linoleate (P ⩽0.003) > lambs fed 3.8% oleate (P ⩽0.01) > lambs fed a non-fat supplemented control diet (P ⩽0.01) when either BF(3) (saponified lipids) or KOH (direct transesterification) was used. Thus, dietary treatment effects on muscle CLA were not affected by catalyst. For the muscle of high-linoleate, high-oleate, and control lambs, CLA was 20.2, 13.9 and 0.0% higher, respectively, with KOH than BF(3), indicating that degradation of CLA by acidic catalysts decreased with lower starting amounts of CLA.

Direct transesterification of total fatty acids of adipose tissue, and of freeze-dried muscle and liver with boron-trifluoride in methanol

The purpose of this study was to demonstrate direct transesterification of fatty acids of tissue total lipids with boron-trifluoride in methanol. Adipose tissue, muscle, and liver samples obtained from market-weight lambs, were transesterified with 14% boron-trifluoride in methanol at 80 °C. Total lipids of additional samples were first solvent-extracted and then transesterified with 14% boron-trifluoride in methanol. Thin layer Chromatographic evaluation revealed quantitative conversion of triacylglycerol- and polar lipid-fatty acids to fatty acid methyl esters using direct transesterification. No differences in fatty acid composition were observed for adipose tissue (p > 0.05); however, for muscle, 20:4 was greater (p = 0.01) with direct transesterification. For liver, greater concentrations of fatty acids were observed for the direct transesterification method (p < 0.02). Weight percentages of adipose and muscle fatty acids were unchanged from 15 to 180min of direct transesterification; however, 120 and 90 min of direct transesterification were required for adipose tissue and muscle, respectively, for complete transesterification. It was concluded that for analysis of total fatty acids, one-step direct transesterification with boron-trifluoride in methanol is a useful and acceptable procedure.

Physiological Responses of Juvenile Rainbow Trout to Fasting and Swimming Activity: Effects on Body Composition and Condition Indices

Abstract The physiological traits that allow fish to survive periods of limited food resources are poorly understood. We assessed changes in proximate body composition, relative organ mass, blood metabolites, and relative weight (Wr ) of sedentary and actively swimming (15 cm/s) juvenile rainbow trout (154–182 mm total length) over 147 d of fasting. Fasting caused measurable responses that were augmented when fish were swimming. Lipids and plasma triacylglycerides declined over time. Proteins were catabolized simultaneously with lipid reserves, but ammonia concentrations in plasma did not increase. The liver somatic index (LSI) did not change substantially over 105 d, suggesting that gluconeogenesis maintained blood glucose concentrations and hepatic glycogen reserves for a substantial period of fasting. The gut somatic index (GSI) and Wr declined linearly during fasting, but the LSI did not decline until after 105 d of fasting. Consequently, the use of different body condition indices could lead to diffe...

Maternal obesity upregulates fatty acid and glucose transporters and increases expression of enzymes mediating fatty acid biosynthesis in fetal adipose tissue depots1

Maternal nutrient restriction leads to alteration in fetal adipose tissue, and offspring from obese mothers have an increased risk of developing obesity. We hypothesized that maternal obesity increases fetal adipogenesis. Multiparous ewes (Columbia/Rambouillet cross 3 to 5 yr of age) carrying twins were assigned to a diet of 100% (Control; CON; n = 4) or 150% (Obese; OB, n = 7) of NRC maintenance requirements from 60 d before conception until necropsy on d 135 of gestation. Maternal and fetal plasma were collected and stored at -80°C for glucose and hormone analyses. Fetal measurements were made at necropsy, and perirenal, pericardial, and subcutaneous adipose tissues were collected from 7 male twin fetuses per group and snap frozen at -80°C. Protein and mRNA expression of fatty acid translocase [cluster of differentiation (CD) 36], fatty acid transport proteins (FATP) 1 and 4, insulin-sensitive glucose transporter (GLUT-4), fatty acid synthase (FASN), and acetyl-coA carboxylase (ACC) was evaluated. Fetal weight was similar, but fetal carcass weight (FCW) was reduced (P < 0.05) in OB versus CON fetuses. Pericardial and perirenal adipose tissue weights were increased (P < 0.05) as a percentage of FCW in OB versus CON fetuses, as was subcutaneous fat thickness (P < 0.001). Average adipocyte diameter was greater (P < 0.01) in the perirenal fat and the pericardial fat (P = 0.06) in OB fetuses compared with CON fetuses. Maternal plasma showed no difference (P > 0.05) in glucose or other hormones, fetal plasma glucose was similar (P = 0.42), and cortisol, IGF-1, and thyroxine were reduced (P ≤ 0.05) in OB fetuses compared with CON fetuses. Protein and mRNA expression of CD 36, FATP 1 and 4, and GLUT-4 were increased (P ≤ 0.05) in all fetal adipose depots in OB versus CON fetuses. The mRNA expression of FASN and ACC was increased (P < 0.05) in OB vs. CON fetuses in all 3 fetal adipose tissue depots. Fatty acid concentrations were increased (P = 0.01) in the perirenal depot of OB versus CON fetuses, and specific fatty acid concentrations were altered (P < 0.05) in subcutaneous and pericardial adipose tissue because of maternal obesity. In conclusion, maternal obesity was associated with increased fetal adiposity, increased fatty acid and glucose transporters, and increased expression of enzymes mediating fatty acid biosynthesis in adipose depots. These alterations, if maintained into the postnatal period, could predispose the offspring to later obesity and metabolic disease.

Fatty acid and sensory characteristics of beef from three biological types of cattle grazing cool-season forages supplemented with soyhulls

Over two consecutive years, the effects of allocating divergent biological types of cattle (n=107) to fescue pasture without supplementation, or fescue or orchardgrass pasture with soyhull supplementation on chemical, fatty acid and sensory characteristics were investigated. Cattle from the two supplemented treatments produced beef that had increased (P<0.05) percentage lipid and decreased (P<0.05) polyunsaturated and n-3 fatty acids compared to the control. However, the n-6 to n-3 ratio was still less than four in beef from the supplemented cattle. Additionally, supplementation did not decrease (P>0.05) the CLA present in the longissimus, which can commonly occur when forage-fed cattle are supplemented concentrates. Although supplementation did not impact (P>0.05) Warner-Bratzler shear force or tenderness, supplementation of soyhulls reduced (P<0.05) the grassy flavor intensity of rib steaks when compared to the control. Biological type did not have a significant influence on most traits analyzed in this study. These results suggest that supplementation of soyhulls to cattle grazing forage can reduce grassy flavor intensity without decreasing CLA proportions, but can reduce the n-3 fatty acid proportions present in the longissimus.

Feeding feedlot steers fish oil alters the fatty acid composition of adipose and muscle tissue

Sixteen steers (441±31.7kg initial body weight) consumed two high concentrate diets with either 0 or 3% fish oil to determine the impact of fish oil, an omega-3 fatty acid source, on the fatty acid composition of beef carcasses. Collected tissue samples included the Longissimus thoracis from the 6th to 7th rib section, ground 10th to 12th rib, liver, subcutaneous adipose tissue adjacent to the 12th rib, intramuscular adipose tissue in the 6th to 7th rib sections, perirenal adipose tissue, and brisket adipose tissue. Including fish oil in the diet increased most of the saturated fatty acids (P<0.01) and proportions of polyunsaturated fatty acids (P<0.06), and decreased (P<0.01) proportions of monounsaturated fatty acids. Dietary fish oil increased (P<0.01) levels of omega-3 fatty acids in sampled tissues, resulting in lower (P<0.01) omega-6:omega-3 ratios. The weight percentages of C20:5 and C22:6 in tissue may provide the recommended daily allowance for humans. Fish oil may have a role in beef niche marketing if there are no deleterious effects on consumer satisfaction.

Maternal Obesity in Sheep Increases Fatty Acid Synthesis, Upregulates Nutrient Transporters, and Increases Adiposity in Adult Male Offspring after a Feeding Challenge

Maternal obesity in women is increasing worldwide. The objective of this study was to evaluate differences in adipose tissue metabolism and function in adult male offspring from obese and control fed mothers subjected to an ad libitum feeding challenge. We developed a model in which obese ewes were fed 150% of feed provided for controls from 60 days before mating to term. All ewes were fed to requirements during lactation. After weaning, F1 male offspring were fed only to maintenance requirements until adulthood (control = 7, obese = 6), when they were fed ad libitum for 12 weeks with intake monitored. At the end of the feeding challenge offspring were given an intravenous glucose tolerance test (IVGTT), necropsied, and adipose tissue collected. During the feeding trial F1obese males consumed more (P < 0.01), gained more weight (P < 0.01) and became heavier (P < 0.05) than F1control males. During IVGTT, Obese F1 offspring were hyperglycemic and hypoinsulinemic (P < 0.01) compared to F1 control F1. At necropsy perirenal and omental adipose depots weights were 47% and 58% greater respectively and subcutaneous fat thickness 41% greater in F1obese vs F1control males (P < 0.05). Adipocyte diameters were greater (P ≤ 0.04) in perirenal, omental and subcutaneous adipose depots in F1obese males (11, 8 and 7% increase vs. control, respectively). When adipose tissue was incubated for 2 hrs with C-14 labeled acetate, subcutaneous, perirenal, and omental adipose tissue of F1 obese males exhibited greater incorporation (290, 83, and 90% increase vs. control, respectively P < 0.05) of acetate into lipids. Expression of fatty acid transporting, binding, and syntheses mRNA and protein was increased (P < 0.05) compared to F1 control offspring. Maternal obesity increased appetite and adiposity associated with increased adipocyte diameters and increased fatty acid synthesis in over-nourished adult male offspring.

Growth and carcass fatty acid composition of beef steers fed soybean oil for increasing duration before slaughter.

Duration of soybean oil (SBO) supplementation needed to enhance carcass conjugated linoleic acid (CLA) and trans-vaccenic (TVA) content was examined using 96 beef steers (293.6±3.9kg) fed a 78% corn-based diet supplemented with SBO for 0, 77, 137, or 189days before slaughter. Duration of SBO supplementation had no effect (P⩾0.15) on animal performance or carcass traits, nor (P⩾0.15), total, total saturated, or total polyunsaturated fatty acids of Longissimus dorsi (LD). Concentrations of CLA in LD were not affected (P⩾0.18) by SBO supplementation. Concentrations of monounsaturated fatty acids (MUFA) decreased linearly (P=0.03) in LD, whereas TVA increased (P=0.04) in adipose tissue and tended (P=0.07) to increase in LD with increasing duration of SBO supplementation. Supplementing SBO to a concentrate-based diet may enhance TVA without impacting CLA, while reducing the MUFA content of lean beef.

A Limousin specific myostatin allele affects longissimus muscle area and fatty acid profiles in a Wagyu-Limousin F2 population,

A microsatellite-based genome scan of a Wagyu x Limousin F(2) cross population previously demonstrated QTL affecting LM area and fatty acid composition were present in regions near the centromere of BTA2. In this study, we used 70 SNP markers to examine the centromeric 24 megabases (Mb) of BTA2, including the Limousin-specific F94L myostatin allele (AB076403.1; 415C > A) located at approximately 6 Mb on the draft genome sequence of BTA2. A significant effect of the F94L marker was observed (F = 60.17) for LM area, which indicated that myostatin is most likely responsible for the effect. This is consistent with previous reports that the substitution of Leu for Phe at AA 94 of myostatin (caused by the 415C > A transversion) is associated with increased muscle growth. Surprisingly, several fatty acid trait QTL, which affected the amount of unsaturated fats, also mapped to or very near the myostatin marker, including the ratio of C16:1 MUFA to C16:0 saturated fat (F = 16.72), C18:1 to C18:0 (F = 18.88), and total content of MUFA (F = 17.12). In addition, QTL for extent of marbling (F = 14.73) approached significance (P = 0.05), and CLA concentration (F = 9.22) was marginally significant (P = 0.18). We also observed associations of SNP located at 16.3 Mb with KPH (F = 15.00) and for the amount of SFA (F = 12.01). These results provide insight into genetic differences between the Wagyu and Limousin breeds and may lead to a better tasting and healthier product for consumers through improved selection for lipid content of beef.