Backfat Samples Research Articles

Effect of saponified high fat sunflower oilcake and lipoic acid

Sheep fat contains relatively high levels of saturated fatty acids while poly-unsaturated fatty acids (PUFA) are toxic to cellulolytic bacteria and are also saturated in the rumen. Stabilization of residual oil in sunflower oilcake by conversion into calcium salts would be advantageous. Alpha lipoic acid acts as an anti-oxidant to ameliorate the effects of oxidative stress caused by high dietary levels of PUFA. Residual oil (14%) in mechanically extracted (expeller) sunflower oilcake (SFOC) was saponifiedin situ and compared in a complete feedlot diet (100 g crude protein and 31 g extractable fat/kg feed) with commercially extracted oilcake containing 2.4% residual oil (control diet with 29 g fat and 123 g crude protein kg feed) fed to four groups of 10 SA Mutton Merino weaner lambs (ca. 23 kg) for nine weeks. Both diets were fed either with, or without a weekly oral dosing of 500 mg α-lipoic acid. Fatty acid composition was determined on back fat samples while thiobarbituric acid-reactive substances (TBARS) were determined on samples of m. longissimus dorsi stored for zero and six months and displayed for six days. The back fat of the lambs on the saponified expeller SFOC diets contained significantly higher levels of saturated fatty acids and lower levels of mono-unsaturated fatty acids. PUFA were unaffected. High TBARS levels (>1.0) were found after six months storage. Non significant increases in TBARS were observed in the groups that received lipoic acid.

Feeding chicory inulin to entire male pigs during the last period before slaughter reduces skatole in digesta and backfat

The effect of chicory inulin in diets for entire male pigs on skatole levels in colon, rectum and in adipose tissue, and on the composition of microbiota in colon and rectum was evaluated. Entire male pigs of the crossbreed [(Landrace × Yorkshire) × Landrace)] (n = 46; final BW = 101 kg) were fed with a control diet or diets containing either 3, 6 or 9% chicory inulin (containing 70% inulin) during the last four weeks before slaughter. Digesta samples for skatole analyses and for microbiological examinations were taken from colon descendens and rectum. Backfat samples were taken for skatole analyses. The skatole levels in adipose tissue were in general low (0.03 μg/g fat). There was a reduction in skatole with increasing dieatary levels of inulin (linear, P = 0.006). Skatole levels in the digesta samples were also reduced (linear, P < 0.002) by increased dietary inclusion of inulin. Pigs fed with increasing levels of inulin showed a reduction of enterobacteria in colon descendens (linear, P = 0.04) and rectum (linear, P = 0.02), and a tendency towards reduced levels of Enterococcus spp in colon descendens (linear, P = 0.09) and rectum (linear, P = 0.08). In conclusion, addition of chicory inulin in the finishing diet is an effective method to reduce skatole levels in digesta and adipose tissue of the entire male pigs, but the inclusion should be at least 6%, corresponding to 4.2% pure inulin.

Lipid Composition of Covering and Intramuscular Fat in Pigs at Different Slaughter Age

To study age-related variations in fatty acid composition of covering and intramuscular fat (IMF), 60 half siblings, Pic X Camborough, of the same age, 30 barrows and 30 gilts, chosen from 10 litters were used. Groups of 20 subjects each, 10 castrated males and 10 females, balanced for litter, were sacrificed at 6, 8.5 and 9.5 months of age, corresponding to the common slaughter age of the three Italian pig production types, at live weights averaging approximately 90, 145 and 160 kg, respectively. Samples of backfat and longissimus thoracis (LT) muscle, taken at the last rib, were analysed. On LT samples, moisture, fat content and drip loss were determined. Fatty acid composition was determined in lipids from subcutaneous adipose tissue and in lipid fractions from LT. Further, backfat lipids were submitted to iodine value (I.V.) determination. The data were evaluated by means of analysis of variance with age at slaughter and sex as the independent variables. As age increased (6, 8.5 and 9.5 months), higher contents of saturated fatty acids (SFA) (36.36, 39.08 and 39.19%, respectively; P<0.01) and monounsaturated fatty acids (MUFA) (41.78, 43.44 and 44.37%, respectively; P<0.01) were observed in backfat, whereas polyunsaturated fatty acids (PUFA) content, PUFA/SFA ratio and I.V. lowered (P<0.01). As total IMF is concerned, by increasing age, MUFA content increased (43.30; 46.76 and 47.28%, respectively; P<0.01), PUFA content decreased (18.63, 15.14 and 14.82%, respectively; P<0.01) and PUFA/SFA decreased as well (P<0.05); neutral lipids followed the same pattern, while an opposite trend was observed in polar lipids. IMF content (1.65%) was modified neither by sex nor age. The study shows that fatty acid composition of subcutaneous and intramuscular fats differs among the 3 slaughtering ages typical of the Italian pig industry. The variations observed, which could be ascribed to the increase of carcass fatness at increasing slaughter age, can affect both the nutritional and technological quality of pork.

Genetic parameters for tissue and fatty acid composition of backfat, perirenal fat and longissimus muscle in Large White and Landrace pigs

Genetic parameters pertaining to the same chemical characteristics of three porcine tissues, that is backfat (BF), perirenal fat (PF) and longissimus muscle (LM), were estimated in centrally tested Large White and Landrace pigs. Animals were fed ad libitum. They were slaughtered at an average BW of 99.6 kg, and samples of BF (both inner and outer layers) and LM were removed at the 13th to 14th rib level of the carcass on the day after slaughter. The data set included 2483 animals recorded for average daily gain (ADG; 35 to 100 kg), estimated carcass lean percentage (LEAN) and lean tissue growth rate (LTGR). Among these animals, around 950 pigs were recorded for lipid content (L%) and water content (W%) of BF and LM and for fatty acid composition (FAC) of BF, whereas FAC of LM was measured on 297 pigs and L%, W%, and FAC of PF on around 210 pigs. Heritabilities (h2) and genetic correlations (ra) were estimated using REML-animal model methodology. Estimates of h2 for L%, W% and FAC of BF, PF and LM were of moderate-to-high magnitude: for example 0.47 ± 0.09 for L% of LM, 0.59 ± 0.11 for W% of BF, 0.45 ± 0.08 for the ratio of polyunsaturated to saturated fatty acids (P/S) of BF, 0.61 ± 0.15 and 0.29 ± 0.10 for the coefficient of unsaturation of lipids (UNSAT, average number of double bonds of unsaturated fatty acids) of PF and LM, respectively. Genetic correlations of L% with P/S or UNSAT were strongly negative (from −0.4 to −0.9) in BF and LM, but not in PF. The ‘between-tissue’ genetic correlations for homologous compositional traits were far from being unity (e.g. ra = 0.57 ± 0.05 ‘between’ BF and PF for UNSAT). Genetic relationships between ADG and tissue compositional traits were globally weak. By contrast, genetic correlations were moderate-to-high between carcass leanness and tissue compositional traits, especially those of fat depots: for example −0.66 ± 0.14 between LEAN and L% of BF, 0.50 ± 0.07 between LEAN and UNSAT of PF, −0.44 ± 0.08 between LEAN and L% of LM, and 0.27 ± 0.03 between LEAN and UNSAT of LM. On the basis of the parameter estimates found here, breeding for higher LTGR is expected to increase the ratio of water to lipids and the unsaturation degree of lipids in subcutaneous BF and, to a lesser extent, in PF. Tissue composition and FAC of LM would be less affected.

Development of combinations of chemically modified vegetable oils as pork backfat substitutes in sausages formulation

Today's consumers look for foods which provide nutrition and pleasure, while safeguarding their health, the result of which is that they increasingly avoid foods containing cholesterol and saturated and trans fatty acids. Chemically modified vegetable oils can help tailor meat products to meet this growing need and at the same time fulfil the technological needs of the meat processing industry. In this study, 16 backfat samples were characterised for their solid fat content (SFC) and melting point and these characteristics were used to design a mixture of chemically modified vegetable oils for use as a pork fat substitute for elaborating sausages. The mixtures were prepared with different vegetable oils bearing in mind with stearic acid content due to its close correlation with the SFC. The backfat was characterised as a function of its SFC and some modified vegetable oil mixtures were proposed, which led to a 10-20% diminution in saturated fatty acids and with a melting point similar to those observed in the backfat. The fatty acid profile pointed to a polyunsaturated/saturated fatty acids ratio higher than 0.4, and an n-6/n-3 fatty acid ratio of less than 4 in both modified vegetable oil mixtures proposed.

Effect of castration on productive performance, carcass characteristics and meat quality of Iberian pig females reared under intensive management systems

Sixty crossbred (Iberian dam × Duroc sire) females, 80 days of age (17.6 ± 0.13 kg body weight, BW), was used to investigate the effect of castration on productive performance, carcass and meat quality and fatty acid profile of backfat (BF). There were 2 treatments (intact females, IF; castrated females, CF) and 5 replicates of 6 pigs per treatment. Pigs were reared indoor under an intensive production system, ovariectomized at 92 days of age (26.1 ± 0.19 kg BW) and slaughtered at 267 days of age (143.6 ± 6.49 kg BW). Meat samples were taken at longissimus dorsi muscle at the level of the last rib and BF samples were taken at the tail insertion. For the entire experiment (18 to 144 kg BW), IF ate less feed and were more efficient than CF ( P < 0.05). Also, IF had less carcass yield ( P < 0.01) and fat thickness at the gluteus medius muscle ( P < 0.05) and tended to have lower backfat depth ( P < 0.10) than CF. However, IF had higher shoulder yield at 2 and at 24 h post mortem ( P < 0.05) and after trimmed ( P < 0.10) than CF. The pH 24 of the semimembranosus muscle tended to be lower for IF than for CF. Also, IF had more moisture (710 vs. 691 g/kg) and less fat (66.4 vs. 91.2 g/kg) in the longissimus dorsi muscle than CF ( P < 0.05). Meat from IF was more lightness (higher L⁎ value; P < 0.01), redder (higher a⁎ value; P < 0.001) and had more intensive color (higher c⁎ value; P < 0.001) than meat from CF. Backfat was more saturated in CF than in IF ( P < 0.05), mostly because of the higher palmitic acid ( P < 0.05) and the lower linolenic acid ( P < 0.05) content. We conclude that intact females have better productive performance and shoulder yield but less carcass yield than castrated females and that castration does not improve meat quality. Therefore, when animal welfare, cost of castration, productive performance and carcass and meat quality traits are considered, the use of intact females rather than castrated females is recommended for the production of Iberian pigs reared under intensive management systems.

Interactive effects of dietary fat source and slaughter weight in growing-finishing swine: II. Fatty acid composition of subcutaneous fat1

Crossbred pigs (n=288) were used to test the interactive effects of dietary fat source and slaughter weight on the fatty acid composition of subcutaneous fat. Pigs were blocked by initial BW (28.1 kg), and, within blocks, pens (8 pigs/pen) were randomly assigned to either grower and finisher diets devoid of added fat (Ctrl) or diets formulated with 5% beef tallow (BT), poultry fat (PF), or soybean oil (SBO). Immediately after treatment allotment, as well as at mean block BW of 45.5, 68.1, 90.9, and 113.6 kg, 1 pig was randomly selected from each pen, slaughtered, and, within 1 h postmortem, samples of backfat were removed from each carcass between the 4th and 8th thoracic vertebra and separated into the inner, middle, and outer layers for fatty acid composition analysis. During the first 17.4 kg of BW gain, percentages of all SFA increased by more than 4% in subcutaneous fat of pigs fed the Ctrl and BT diets, but decreased by 4.4 and 7.7% in pigs fed the PF and SBO diets, respectively (fat source x slaughter weight, P<0.001). Proportions of all MUFA in subcutaneous fat from BT-fed pigs increased by 6.1% during the first 17.4 kg of BW gain, but MUFA percentages in SBO-fed pigs decreased by 9.1% between 28.1 and 45.5 kg (fat source x slaughter weight, P<0.001). Conversely, percentages of all PUFA from SBO-fed pigs increased by 39.9%, whereas PUFA concentrations in BT-fed pigs decreased by 12.6% as slaughter weight increased from 28.1 to 45.5 kg (fat source x slaughter weight, P<0.001). Resultant iodine values (IV) of subcutaneous fat from SBO-fed pigs increased (P<0.05) from 73.5 to 85.2 within the first 17.4 kg of BW gain, and remained elevated above those of their contemporaries fed the Ctrl, BT, or PF diets at each subsequent slaughter weight (fat source x slaughter weight, P<0.001). The inner backfat layer had the greatest (P<0.05) proportions of all SFA and the least (P<0.05) proportions of all PUFA, whereas the outer layer had the least (P<0.05) percentages of all SFA but the greatest (P<0.05) percentages of all MUFA. Even though the middle and outer subcutaneous fat layers had similar (P>0.05) PUFA percentages, the greatest (P<0.05) and least (P<0.05) IV were in the outer and middle layers, respectively. As expected, the fat source included in swine diets was responsible for the fatty acid compositional changes in subcutaneous fat, yet the results of this study indicate that feeding 5% SBO dramatically increased the polyunsaturation of subcutaneous fat within the first 17.4 kg of BW gain, with backfat IV exceeding 80 thereafter.

Interactive effect of ractopamine and dietary fat source on pork quality characteristics of fresh pork chops during simulated retail display1

Crossbred pigs (n = 216) were used to test the interactive effect, if any, of ractopamine (RAC) and dietary fat source on the performance of finishing pigs, pork carcass characteristics, and quality of LM chops during 5 d of simulated retail display (2.6 degrees C and 1,600 lx warm-white fluorescent lighting). Pigs were blocked by BW and allotted randomly to pens (6 pigs/pen), and, after receiving a common diet devoid of RAC for 2 wk, pens within blocks were assigned randomly to 1 of 4 diets in a 2 x 2 factorial arrangement, with 5% fat [beef tallow (BT) vs. soybean oil (SBO)] and RAC (0 vs. 10 mg/kg). Diets were formulated to contain 3.1 g of lysine/Mcal of ME and 3.48 Mcal/kg of ME. Across the entire 35-d trial, pigs fed RAC had greater (P < 0.01) ADG and G:F, but RAC did not affect (P = 0.09) ADFI; however, performance was not affected (P >or= 0.07) by dietary fat source. Carcass weight, LM depth, and lean muscle yield were increased (P < 0.01), whereas fat depth was decreased (P = 0.01), in carcasses from RAC-fed pigs; however, carcass composition measures were similar (P >or= 0.27) between fat sources. Feeding 10 mg/kg of RAC reduced (P <or= 0.04) the proportions of SFA and MUFA and increased (P < 0.01) the proportion of PUFA and the iodine value, in pork backfat. Conversely, backfat from carcasses of BT-fed pigs had greater (P < 0.01) percentages of SFA and MUFA, and lower (P < 0.01) percentages of PUFA, than backfat from SBO-fed pigs. Moreover, the PUFA:SFA and iodine value were considerably reduced (P < 0.01) by including BT in swine finishing diets. The LM from pigs fed RAC had greater pH values (P = 0.03) and received greater (P <or= 0.01) American and Japanese color scores during retail display. The LM from RAC-fed pigs had lower (P <or= 0.02) L*, a*, and b* values, whereas the LM of SBO-fed pigs received greater (P < 0.01) subjective color scores and b* values, as well as lower L* values, than the LM of BT-fed pigs. Across the 5-d display period, oxidative rancidity was not affected by dietary RAC (P = 0.58) or fat source (P = 0.47). Neither RAC nor fat source altered LM cooking losses and shear force values. Feeding 10 mg/kg of RAC will improve rate and efficiency of gain, carcass composition, and LM quality. And, even though fatty acid composition of backfat samples was altered by dietary fat source, performance and carcass composition, as well as quality during 5 d of retail display, were similar when pigs were fed diets formulated with BT or SBO.

Effects of temperature stress on growth performance and bacon quality in grow-finish pigs housed at two densities

Managing stressors is essential for optimizing pig growth performance. To determine the effects of temperature and space allocation on growth performance and carcass characteristics, pigs were housed within their thermoneutral zone, at 23.9 degrees C, or above their thermoneutral zone, at 32.2 degrees C, and were provided either 0.66 or 0.93 m(2)/pig for the final 35 d of the grow-finish period. Individual BW were recorded on d 1, 10, 20, and 30. At slaughter, carcass measurements and samples of backfat and belly fat were collected. Final BW was decreased (P < or = 0.05) from 113 to 103 kg for pigs housed at 32.2 degrees C. The ADG was reduced (P < 0.05) for pigs housed at 32.2 degrees C (0.89 vs. 0.54 kg/d), as was G:F (0.28 vs. 0.24). Housing at 0.66 m(2)/pig resulted in pigs that were lighter (P < or = 0.05), at 106 compared with 110 kg, as a result of decreased (P < or = 0.05) ADG (0.78 to 0.65 kg/d) and decreased (P < or = 0.05) G:F (0.275 to 0.255) compared with pigs housed at 0.93 m(2)/pig. Pigs housed at a greater spatial allocation had elevated (P < or = 0.05) ADFI. The interaction of housing at 32.2 degrees C and decreasing spatial allocation increased (P < or = 0.05) the adipose iodine value from 66.8 to 70.4, decreased (P < or = 0.05) the saturated:unsaturated fatty acids ratio from 0.59 to 0.56, and increased (P < or = 0.05) the n-6:n-3 from 23.56 to 25.27. Decreased spatial allocation resulted in decreased (P < or = 0.05) belly weights. Although increased temperature did not affect belly weight, the 32.2 degrees C pigs had decreased (P < or = 0.05) raw and cooked slice weights, increased (P < or = 0.05) percentage lean of bacon, increased (P < or = 0.05) lean:fat ratio of bacon slices, increased (P < or = 0.05) raw slice scores, and increased (P < or = 0.05) quantity of collagen in belly fat. Some of these changes may have resulted from changes in lipid metabolism. Increasing spatial allocation in the 32.2 degrees C pigs decreased fatty acid synthase (P = 0.03) and stearoyl-CoA desaturase- 1 (P = 0.08) mRNA expression in adipose tissue. The results from this study demonstrated decreased growth, carcass lipid quality, and bacon quality in pigs housed at temperatures above the thermoneutral zone; however, increasing the spatial allocation for housing may be a means to ameliorate the negative effects of temperature stress.

Fatty acids composition of Colonnata Lard from two different swine breeds

The study compares the fatty acid composition of the Colonnata lard obtained from two different swine breeds, Large White (LW) and Cinta Senese (CS), during a one year long curing period. Samples of backfat were obtained from the carcass of three animals per breed and disposed into six different marble boxes according to the procedure of the disciplinary production of PGI “Lardo di Colonnata”. During curing period individual lard samples were collected monthly from each marble box. The fatty acid composition of pig backfat reflected the differences in the dietary regimen and in the rearing system of the two breeds. LW swine, in fact, were fed a commercial concentrate and reared in an intensive system, whereas CS swine were fed a diet composed by a commercial concentrate supplemented with acorn and reared in an outdoor system. Lard from LW contained higher amount of saturated fatty acids than lard from CS, whereas the content of unsaturated fatty acids (mainly monounsaturated fatty acids) was lower. During the curing period the trend of lard fatty acids composition was different in the two breeds: the lard from CS seemed to be more susceptible to a faster hydrolysis of fatty acids than lard from LW, especially for the monounsaturated fatty acids, while the lard from LW seemed to be more susceptible to a faster hydrolysis of PUFA n-3.

Effects of dried distillers grains with solubles and extruded expelled soybean meal on growth performance and carcass characteristics of grow-finish pigs (2007)

A total of 120 barrows (maternal line PIC 1050) with an initial BW of 105.7 lb were used in an 83-d trial to study the effects of dried distillers grains with solubles (DDGS) and extruded expelled soybean meal (EESM) on growth performance and fat quality. Pigs were blocked by weight and randomly allotted to one of six treatments with two pigs per pen and 10 pens per treatment. Diets were: a corn-soybean meal control diet with no added fat, corn-EESM diet with no added fat, corn-EESM diet with 15% DDGS, corn-soybean meal diet with 15% DDGS, and 1.55% choice white grease (CWG), corn-soybean meal diet with 3.25% CWG, and corn-soybean meal diet with 4.7% CWG. Diets were formulated to have three dietary iodine value (IV) levels (42, 55, and 62) to compare the impact of fat source within dietary IV levels. On d 83, jowl and backfat samples were collected. Pigs fed the control diet, EESM, or 4.7% CWG had increased ADG compared with pigs fed the diet containing EESM with 15% DDGS. Pigs fed the control diet had increased ADFI compared with all other treatment. Pigs fed EESM with 15% DDGS and the diets with 4.7% CWG had improved F/G compared with pigs fed the control and pigs fed DDGS with CWG. Pigs fed high CWG had greater (P<0.05) loin depth compared with pigs fed low CWG. Pigs fed either of the diets with 15% DDGS had increased backfat IV compared with pigs fed diets without DDGS. Pigs fed EESM had increased backfat IV when compared with the control diet or diets with 3.25 or 4.7% CWG. Adding DDGS to the diet or using EESM increased IV of jowl fat. Adding CWG to the control diet also increased IV of jowl fat. Feeding ingredients with higher levels of unsaturated fat, such as EESM and DDGS, had a greater impact on fat IV than CWG even when diets were formulated to similar IV levels.; Swine Day, 2007, Kansas State University, Manhattan, KS, 2007

Effects of dried distillers grains with solubles on growth performance and fat quality of finishing pigs

A total of 1,112 pigs were used in a 78-d growth assay evaluating the effects of increasing dried distillers grains with solubles (DDGS, 0, 5, 10, 15, or 20%) on pig growth performance and carcass characteristics. At the end of the trial, jowl fat, belly fat, and backfat samples were collected and analyzed for fatty acid profile and iodine value (IV). From d 0 to 78, ADG and ADFI decreased (linear; P 0.22) in loin depth, but increasing DDGS tended to decrease (P<0.09) backfat and fat-free lean index (FFLI). Backfat, jowl fat, and belly fat iodine values and percentage C 18:2 fatty acids increased (linear, P<0.02) with increasing DDGS in both the “topped” pigs marketed 21 d before trial conclusion and pigs marketed at trial completion. Increasing DDGS decreased (linear, P<0.05) percentage saturated fatty acids in backfat and belly fat in both marketing groups and percentage saturated fatty acids in jowl fat with increasing DDGS in the diet in the pigs marketed at trial completion. Barrows had decreased (P<0.04) belly fat iodine values and percentage 18:2 fatty acids when compared to gilts. Barrows also had increased (P<0.05) jowl fat and belly fat percentage 18:2 fatty acids when compared to gilts. Based on these results and previous research trials, dried distillers grain with solubles from this source can be fed up to 15% before seeing reductions in ADG; however, the increase in iodine value and decrease in dressing percentage must be considered in determining the economic value of DDGS.

Effects of increasing added choice white grease in corn and sorghum-based diets on growth performance and fat quality characteristics of finishing pigs (2007)

One hundred twenty crossbred barrows and gilts (TR4 × 1050) with an initial weight of 119.9 lb were used in an 83-d experiment to evaluate the effects of increasing added fat to corn or sorghum-based diets on growth performance and fat quality characteristics of finishing pigs. Treatments were arranged in a 2 × 2 × 3 factorial based on grain source (corn or sorghum), gender, and added fat (0, 2.5, or 5% choice white grease, CWG). At the end of the trial, jowl fat and backfat samples were collected. Pigs fed sorghum-based diets had increased (P<0.01) ADG compared with pigs fed corn-based diets. Pigs fed increasing CWG had increased (P<0.01) ADG. Pigs fed corn-based diets tended to have improved (P<0.06) dressing percentage, 10 rib BF, and percentage lean when compared with pigs fed sorghum-based diets. Barrows tended to have greater (P<0.06) dressing percentage and decreased (P<0.07) percentage lean when compared to gilts. Pigs fed increasing CWG had increased (P<0.02) 10 rib backfat, tended to have increased (P<0.08) hot carcass weight, and tended to have decreased (P<0.07) percentage lean. There was a fat level by grain source interaction (P<0.03) for percent C 18:2 fatty acids and iodine value in jowl fat. The interaction was due to the greatest increase in IV and percentage C 18:2 fatty acids occurring when CWG was increased from 2.5 to 5% for corn-based diets, while the greatest increase was from 0 to 2.5% CWG for sorghum-based diets. Despite this interaction, adding CWG increased (linear, P<0.02) percentage C 18:2 fatty acids and iodine value in jowl fat. Pigs fed corn-based diets had increased (P<0.01) iodine values and percentage C 18:2 fatty acids in jowl fat and backfat compared with pigs fed sorghum-based diets. Increasing dietary CWG increased (P<0.01) iodine value in jowl fat and backfat, increased (P<0.01) percentage C 18:2 fatty acids in backfat, tended to increase (P<0.06) percentage 18:2 fatty acids in jowl fat, and decreased (P<0.01) percentage saturated fatty acids in jowl fat and backfat. In summary, substituting sorghum for corn in diets for finishing pigs can be an effective way to reduce iodine value without affecting growth.

Effects of choice white grease or soybean oil on growth performance and carcass characteristics of grow-finish pigs (2007)

A total of 144 barrows and gilts (PIC) with an initial BW of 97 lb were used to evaluate the effects of dietary fat source and duration of feeding on growth performance and carcass fat quality. Dietary treatments included a corn-soybean meal control diet with no added fat or a 2 × 4 factorial arrangement with 5% choice white grease (CWG) or soybean oil and with-drawal of the fat 0, 14, 28, or 56 days before market (82 days). At the end of each feeding duration, pigs were switched to the control diet. At the end of the study (d 82), jowl fat and backfat samples were collected. Lengthening the duration of feeding soybean oil increased (quadratic, P<0.01) ADG and improved F/G. Increasing the feeding duration of CWG had no effect on ADG, but improved (quadratic, P<0.01) F/G. Increasing the feeding duration of CWG or soybean oil increased (quadratic, P<0.02) dressing percentage with the improvement being greater (P<0.06) for pigs fed CWG compared to pigs fed soybean oil. Gilts had increased (P<0.01) iodine value (IV; more unsaturated fat) compared to barrows. Increasing feeding duration of either soybean oil or CWG increased (quadratic, P<0.01) IV compared to pigs fed the control diet. In summary, adding fat to the diet improved pig growth performance but increased jowl fat and backfat IV. Feeding fat during any stage influenced jowl IV at market with duration of feeding having the greatest response with soybean oil.; Swine Day, 2007, Kansas State University, Manhattan, KS, 2007

Quality assessment of Iberian pigs through backfat ultrasound characterization and fatty acid composition

Five batches of Iberian pig backfat of different breeds and with differing feeding regimes were analysed as to their fatty acid composition and textural, thermal and ultrasonic properties. The feeding regime affected the backfat composition more than the breed of the animals. The higher the oleic acid content in the feeding regime, the higher the monounsaturated fatty acid content in the samples. Ultrasonic velocities ranged from 1609 to 1631 m/s. A change in the slope of the velocity versus temperature curve was found at 6 °C, coincident with a change in the melting rate found in the differential scanning calorimetry. Discriminant analysis using ultrasonic measurements allowed 94.7% of the samples to be correctly classified in the batches considered, while the use of the fatty acids composition correctly classified 86.2% of the samples. Therefore, ultrasonic techniques could be useful in the characterization and classification of backfat samples from Iberian pigs.

Quantitative trait loci mapping for fatty acid composition traits in perirenal and back fat using a Japanese wild boar × Large White intercross

Here, we analysed quantitative trait loci (QTL) for fatty acid composition, one of the factors affecting fat quality, in a Japanese wild boar x Large White cross. We found 25 significant effects for 17 traits at 13 positions at the 5% genome-wise level, of which 16 effects for 12 traits at 10 positions were significant at the 1% level. QTL for saturated fatty acids (SFA) in back fat were mapped to swine (Sus scrofa) chromosomes (SSC) 1p, 9 and 15. QTL for unsaturated fatty acids in back fat were mapped to SSC1p, 1q, 4, 5, 9, 15 and 17. Using a regression model that fits back fat thickness as a covariate, two of the QTL for linoleic acid content on SSC4 and SSC17 were not significant, but one QTL for total SFA composition was detected on SSC5 with correction for back fat thickness. Wild boar alleles at six of seven QTL tended to increase SFAs and to decrease unsaturated fatty acids. QTL for fatty acid composition in perirenal fat were mapped on SSC2, 3, 4, 5, 6, 14, 16 and X. QTL for melting point (in back fat samples) were mapped on SSC1, 2 and 15. Wild boar alleles in QTL on SSC1 and SSC15 were associated with elevated melting points whereas those on SSC2 were associated with lower melting point measurements.

Influence of volatile compounds on the development of off-flavours in pig back fat samples classified with boar taint by a test panel

Dynamic Head Space methodology was applied to evaluate the possible contribution of some volatile compounds to the development of boar taint in pig backfat samples with low concentrations of skatole and androstenone, but which had previously been classified as tainted by a trained test panel. Volatile compounds were collected in a trap of graphited charcoal and analysed by GC–MS in Scan mode. Aldehydes and short chain fatty acids, compounds that play a significant role in the development of undesirable aromas in food products, were the main classes of compounds identified in this study, although the possible contribution of other compounds that were detected in a minor proportion – such as alcohols and ketones – was evaluated. Styrene and 1,4-dichlorobenzene, compounds that may have come from an external contamination, showed a high concentration in the samples classified with boar taint, so these compounds could have been responsible for the development of some off-flavours in the fat samples studied in this work. In the same study, skatole and androstenone were also determined by normal phase HPLC and GCMS, respectively.

Liquid chromatographic-electrospray tandem mass spectrometric method for the determination of mebendazole and its hydrolysed and reduced metabolites in sheep muscle

A quantitative liquid chromatographic-electrospray tandem mass spectrometric method for the determination of mebendazole, its hydrolysed metabolite and its reduced metabolite in sheep muscle has been optimised, validated and applied in a depletion study of the mebendazole-derived residues from edible tissues of sheep after a single oral treatment with the commercial formulation Ovitelmin ®. The anthelmintic compounds were extracted with ethyl acetate after the sample mixture had been made alkaline. The liquid chromatographic separation was performed on a reversed phase C 18 column. Gradient elution with a mobile phase consisting of water containing 0.1% formic acid and acetonitrile was applied. Because of the detection by a very selective tandem quadrupole mass spectrometer in MS/MS mode after atmospheric pressure electrospray ionisation, the presented drug residue analysis method is very sensitive. The confirmatory method was validated according to the revised EU requirements. Most parameters were found to be conform proved to be with the criteria. The validation limit or the minimum required performance limit for sheep muscle tissue was set at 10 μg kg −1. The evaluated validation parameters were stability, specificity, recovery, precision (repeatability and within-laboratory reproducibility), analytical limits (decision limit and detection capability) and applicability. The decision limit values obtained for mebendazole, the hydrolysed and the reduced metabolite were 11, 12 and 13 μg kg −1, respectively. The detection capabilities for these substances were 13, 15 and 16 μg kg −1, respectively. In the depletion study, residues of mebendazole and its two metabolites could be measured in muscle, liver, kidney as well as back fat samples. After 1 day of excretion, the residue concentrations ranged from 21 to 7630 μg kg −1. The highest residue concentrations were found in the liver samples. Except for the back fat samples, the highest residue values were always measured for the reduced metabolite. This substance in liver and the hydrolysed metabolite in kidney was found for 14 days after administration.

The effects of body composition on the pharmacokinetics of subcutaneously injected ivermectin and moxidectin in pigs.

Macrocyclic lactones are characterized by their long persistence in animals because of their extensive distribution into fat. This study examined the influence of body condition on the disposition of ivermectin (IVM) and moxidectin (MXD) in blood and fat following subcutaneous (s.c.) drug administration. 'Fat' and 'thin' lines of pigs were established using two different diets. All animals were then injected with either MXD or IVM at 300 microg/kg and blood samples were taken at regular intervals until slaughter. Two IVM-treated animals from each diet group were slaughtered at either 3 days or 3 weeks posttreatment. Two MXD-treated animals from each diet group were slaughtered at 3 days, 3, 6 or 9 weeks after treatment. Samples of backfat were taken from all animals at slaughter. Fluorescence HPLC was used to determine the concentrations of MXD or IVM in the plasma and fat samples. The plasma IVM concentration peaked more rapidly in the thin IVM treated pigs compared with the fat pigs. The concentration of IVM in backfat was significantly lower in the thin animals slaughtered 3 weeks after treatment. The MXD plasma concentration peaked within the first hour in both the thin and fat groups, but from 12 h posttreatment there was a higher MXD concentration in the plasma of the fat pigs resulting in MXD being detectable in these pigs for 28 days compared with only 17 days in the thin pigs. Despite this difference in plasma persistence no differences were seen in the MXD concentration of backfat between fat and thin animals. Body condition influenced the kinetic disposition of IVM and MXD following s.c. drug administration with both drugs being less persistent in thin compared with fat animals.

Homogeneous stopped-flow fluoroimmunoassay using europium as label

A competitive homogeneous fluoroimmunoassay (FIA) based on the use of europium(III) as label together with kinetic methodology, is described for the first time. This approach has been applied to the determination of skatole, a compound causing boar-taint, in pig back fat samples. The analytical signal was obtained by measuring the initial rate of the dissociation reaction of europium(III) from the tracer through the formation of an intense luminescent chelate. This initial rate is higher for the free tracer than for that corresponding to the tracer bound to the antibody, and it is directly related to the analyte concentration. Each kinetic measurement was obtained in less than 1 s by using stopped-flow (SF) mixing technique. Benzoyltrifluoroacetone, tri- n-octylphosphine and Triton X-100 were used to obtain an adequate luminescent signal. The dynamic range of the calibration graph of the method is 30–300 ng ml −1 and the calculated detection limit is 11 ng ml −1. The precision, obtained for two skatole concentrations, 50 and 150 ng ml −1, and expressed as relative standard deviation ( n=11), was lower than 6.5%. The method was applied to the analysis of pig back fat samples with recoveries ranging from 92 to 108%.