Backfat Fatty Acid Composition Research Articles

Performance, carcass characteristics, and lipid metabolism in growing and finishing Simmental steers fed varying concentrations of copper.

An experiment was conducted to determine the effects of dietary copper (Cu) on performance, carcass characteristics, and lipid metabolism in Simmental steers. Thirty-six Simmental steers (329.3 +/-11.4 kg) were stratified by weight and randomly assigned to treatments. Treatments consisted of the following: control (no supplemental Cu) and 10 or 40 mg Cu/kg DM from Cu sulfate. Each treatment consisted of six replicate pens, with each pen containing two steers. A corn silage-soybean meal-based diet was fed for 56 d. Steers were then switched to a high concentrate diet. Performance was not affected by treatment during the growing or finishing phases. Plasma Cu concentrations were higher (P < 0.05) in steers receiving supplemental Cu by d 56 of the growing phase and remained higher (P < 0.05) at all 28-d sampling periods during the finishing phase. Liver Cu concentrations were higher (P < 0.001) in steers receiving supplemental Cu at the end of the growing phase and on d 84 and at the end of the finishing phase. Steers supplemented with 40 mg Cu had higher (P < 0.001) liver Cu concentrations than those supplemented with 10 mg Cu/kg DM. Serum and longissimus muscle cholesterol concentrations were similar between treatments. Longissimus muscle and backfat fatty acid composition was similar between treatments. These results indicate that Cu supplementation given to Simmental steers increased Cu status but had no effect on performance, carcass characteristics, or lipid or cholesterol metabolism.

Influence of a high ambient temperature on stearoyl-CoA-desaturase activity in the growing pig

An experiment was conducted to determine the influence of a high ambient temperature on the stearoyl-CoA-desaturase activity and fatty acid composition of backfat, leaf fat, Longissimus dorsi muscle and liver, in the growing pig. Eighteen Large White X Landrace castrated pigs (20 kg body weight) were divided into three groups: I (31°C, ad libitum), II (20°C, pair-fed on the 31°C group) and III (20°C, ad libitum) until 35 kg body weight. At 20°C, the level of feed intake had no effect on stearoyl-CoA-desaturase activity, whatever the tissue (groups II and III). At similar levels of feeding, (groups I and II), the stearoyl-CoA-desaturase activity was lower at 31°C ( P<0.001) than at 20°C, regardless of the tissue, with the exception of the hepatic stearoyl-CoA-desaturase activity, which was similar in all three groups. This reduction of the stearoyl-CoA-desaturase activity at 31°C could be related to a decrease in the monounsaturated fatty acid percentage in all the tissues, in hot conditions. The present results show that changes in fatty acid composition caused by environmental temperature, in the pig, may be attributed at least in part to an alteration in the stearoyl-CoA-desaturase activity.

Selective improvement of porcine fat firmness by a diet enriched in medium‐chain fatty acids

AbstractThe effects of 4% fat either rich in medium‐chain fatty acids (MCFA; saturated fat) or in polyenoic fatty acids (PUFA; unsaturated fat) isoenergetically exchanging carbohydrates of a low‐fat diet (control) on performance and product quality were evaluated with 180 growing pigs. Growth, carcass and meat quality were not affected by the fat treatments. Although elevated in blood serum, cholesterol was not increased in belly meat when the MCFA‐rich diet was fed. Fatty acid composition of backfat reflected dietary fat composition. The significantly lowest shelf life and melting temperatures were found with the unsaturated‐fat diet. When compared with control, fat tissue PUFA contents were slightly higher in the saturated‐fat diet, and fat melting temperatures were somewhat lower. In contrast, the use of this MCFA‐enriched diet increased penetrometer firmness in pure 4°C temperated backfat by more than 50% as compared with control and to about the tenfold level of the firmness obtained in the unsaturated‐fat diet. Impression of flavour and odor in lean and fatty meat were not systematically affected by the diets. The present results show a high potential of MCFA‐enriched diets to selectively increase fat firmness in pigs without greater undesired side effects on other traits of product quality.

Effects of exogenous porcine somatotropin on the development of fat cells and fatty acid composition in backfat of live finishing pigs

The effects of long-term application of recombinant porcine somatotropin (pST) to Landrace pigs on the development of backfat thickness, fat cells and fatty acid composition were investigated from about the 116th to the 186th day of life. Biopsy samples from the backfat of 56 castrates were taken at the beginning of treatment and after 5 and 10 weeks. The daily injection of 2 or 4 mg of pST induced a considerable decrease in backfat growth compared to untreated controls. This was attributed to a decreased size (about 18–20%) and number (about 13–25%) of fat cells. The higher dose of 4 mg pST/day induced a greater restriction of fat growth. This was obviously based on differences in fat cell number. Furthermore, pST treatment delayed the normal decrease of unsaturated fatty acids (C 18:2; C 18:3) during the period of growth examined. Therefore, the percentages of unsaturated fatty acids increased, indicating changes in fat cell metabolism of pST treated pigs.

Carcass and meat quality characteristics and backfat fatty acid composition of swine as affected by the consumption of peanuts remaining in the field after harvest.

Carcass composition, meat quality characteristics and changes in backfat fatty acid composition of swine that were allowed to obtain part or all of their weight gain during the growing-finishing period from gleaning peanuts remaining in the field after harvest were evaluated. Thirty-six cross-bred pigs (18 barrows, 18 gilts) were allotted evenly among the following six treatments: 1) fed a corn-soybean meal-based diet (C) from 26 to 104 kg (CCC); 2) gleaned peanuts (P) from 26 to 102 kg (PPP); 3) C from 26 to 78 kg and P from 78 to 103 kg (CCP); 4) P from 26 to 55 kg and C from 55 to 105 kg (PCC); 5) C from 26 to 56 kg and P from 56 to 103 kg (CCP); 6) P from 26 to 79 kg and C from 79 to 106 kg (PPC). Carcasses from all treatment groups were similar in composition. Carcass fat of pigs in CPP, PPC and, in particular, PPP groups was softer than that from pigs in CCC, CCP and PCC groups. Ratio of unsaturated to saturated fatty acids in backfat increased in proportion to the amount of weight gained while pigs gleaned peanuts. Loins from pigs in the PPP and CPP treatment groups received lower marbling scores than those from the CCC group, but the fat content of the loin was not affected by treatment. No differences were detected between treatment groups in shear force values or sensory panel attributes of broiled loin chops, or in thiobarbituric acid values of vacuum packaged loin sections frozen for 4 mo.(ABSTRACT TRUNCATED AT 250 WORDS)

INFLUENCE OF DIETARY FAT LEVEL ON GROWTH AND BODY COMPOSITION OF THE NEONATAL PIG

Four Yorkshire piglets, from each of 18 litters, were randomly allotted within litters, to four treatment groups 12 h after birth. Group 1 (Control) continued to be suckled by sows; the remaining piglets were reared artificially on a semi-synthetic liquid diet containing either 25% soybean oil (SBO) (group 2) or 3% SBO plus 22% lactose (groups 3 and 4). At 7, 14 and 21 days of age, 24 pigs from six litters were killed. Piglets on the 25% SBO diet grew faster (P &lt; 0.05) than those on the 3% SBO diet while the growth rate of the suckled piglets tended to be between the growth rates of those on the two SBO diets. Body fat content increased with the fat content in the diet and with age. The protein:fat ratio was greatest in the piglets on the 3% SBO diet and least in the suckled piglets. The fatty acid composition of backfat changed, primarily during the first week of life, towards that of the dietary fat. This was evident even in piglets on the low fat-high carbohydrate (3% SBO) diet. The composition of the fat deposited in piglets on the 3% SBO group indicated preferential utilization of essential fatty acids and little de novo synthesis of fatty acids. The amount and type of fat deposited by piglets fed the 3% SBO diet, together with preliminary evidence of low incorporation of radioactivity from (U14C) glucose with adipose tissue fatty acids in vivo, suggest that the de novo fatty acid biosynthesis in adipose tissue of piglets is not as high as previously reported (Mersmann et al. 1973). Key words: Neonatal pigs, fat deposition, fatty acid biosynthesis.

A note on the fatty acid composition of backfat from boars in comparison with gilts and barrows

ABSTRACTBackfat from each of 25 littermate boars, barrows and gilts, which were crosses of the Large White and British Landrace breeds slaughtered at approximately 90 kg live weight, was analysed for fatty acid composition. Fat from boars had a significantly higher proportion of total unsaturated fatty acids (61·6%) compared with barrows (60·2%), This sex difference was due to a lower palmitic acid (16:0) content and higher linoleic (18:2) and linolenic (18:3) fatty acid levels in backfat of boars. Gilts were intermediate to boars and barrows in the degree of unsaturation of backfat.

Fatty acid composition of backfat in large white pigs selected for low backfat thickness

Samples of midback fat were taken from 157 Large White boars and analysed for fatty acid composition and melting point of lipid. Seventy-seven boars were from a line showing fast efficient growth and low backfat depth (selection line) and 80 from a random-mated control line. All were performance-tested from 27 to 87 kg liveweight on ad libitum feeding. Selection line pigs required 6 % less feed per kilogramme liveweight gain and had thinner backfat at each point of measurement (16–27 %) than the controls but there was no line difference in daily liveweight gain. Selection line pigs had ‘eye muscles’ which were slightly paler and had a greater drip loss than the controls. The fatty acid composition and melting point of the lipid extracted from backfat was similar between the lines except that the concentration of linoleic acid (C18:2) in both inner and outer layers was some 14% higher in the selection line. There were significant negative correlations between the concentration of C18:2 and the various backfat measurements. Positive correlations were found between some backfat measurements and the concentration of stearic acid (C18:0), particularly in the selection line. Variation in melting point in both layers was more strongly related to variation in the concentration of C18:0 than to that of any other fatty acid.

The fatty acid composition of backfat from Pietrain and Large White pigs

SUMMARYThe fatty acid composition of backfat from Pietrain and Large White pigs was examined. Both the inner and outer layers of Pietrain backfat had higher concentrations of unsaturated fatty acids and lower concentrations of saturated fatty acids. Pietrains consequently had relatively soft fat.A pair-feeding experiment was conducted with Large White and Pietrain pigs to determine whether these differences could be explained by the lower voluntary feed intake of Pietrains. The results showed that the Large Whites continued to accumulate relatively saturated fatty acids even at the lower level of feeding. It was concluded that the differences in the fatty acid composition of backfat reflect genetic differences in the capacity for fat deposition between the two breeds.

INFLUENCE OF DIETARY VOLATILE FATTY ACID MIXTURES ON PERFORMANCE AND ON FAT COMPOSITION OF GROWING PIGS

Two experiments were conducted to evaluate the acceptability, calculated digestible energy, influence on performance, and effect on fatty acid composition of backfat when a mixture of volatile fatty acids (VFA) or of a sodium salt of these fatty acids (Na VFA) was fed to pigs. The weight percent of the VFA mixture was 40 acetic, 40 propionic and 20 butyric acid. Adding 2 to 8% VFA or Na VFA to the diet, without adjustment for digestible energy or total protein, did not influence feed intake or rate of gain. Dietary levels of 10 or 12% VFA or Na VFA depressed daily gain. When 4% VFA or Na VFA was fed from an initial weight of 12 kg, feed intake was not altered in comparison with that of pigs fed a control diet. Rate of gain averaged 0.64 kg per day for pigs fed either VFA or Na VFA, compared with 0.60 kg for control pigs. The digestible energy values of the VFA and Na VFA, based on calculated energy conversion from 38 to 75 kg liveweight, were higher than the gross energy values of the compounds determined by oxygen bomb calorimetry, presumably because of a synergistic action of VFA with other energy sources in the diet. Carcass backfat thickness, area of loin and lean in the ham face were not significantly altered by feeding VFA or Na VFA. When pigs received up to 12% VFA or Na VFA, weight percent oleic acid in the outer backfat was increased (P &lt; 0.05) from 49.9% in the control pigs to between 52.7 and 53.3 percent. There was no influence on backfat composition when 4% VFA or Na VFA was fed continuously.

Fatty Acid Composition of the Inner and Outer Layers of Porcine Backfat as Affected by Energy Level, Sex and Sire

SUMMARY— The effects of energy level, sex and sire upon the fatty acid composition of porcine fackfat were studied in two separate experiments. In both experiments, the inner layer of backfat consistently contained more total saturated fatty acids, primarily accounted for by stearic acid, and contained less palmitoleic, oleic, and linoleic acids than the outer layer. None of the variables in either experiment significantly (P &gt;.0.5) affected the differences between layers.In Experiment 1, energy levels below 80% of full feed significantly (P &lt; .01) decreased stearic acid content and increased linoleic acid content. In Experiment 2 the fatty acid composition of backfat from pigs fed 80% of full feed did not differ significantly (P &gt; .05) from full‐fed pigs.Backfat from spayed gilts had significantly (P &lt; .01) less linoleic acid than that from boars or barrows, while boars had a significantly (P &lt; .01) higher content of linoleic acid than the other sexes. In Experiment 1, the backfat from barrows contained significantly (P &lt; .01) more stearic acid than that from gilts.The data from both experiments indicated that sire significantly (P &lt; .01) affected the linoleic acid content of the backfat, while the results of Experiment 2 also showed significant (P &lt; .01) sire effects upon the palmitic, palmitoleic, and stearic acid contents.