Fatty acid profiles of the total lipids and lipid oxidation in pork muscles as affected by canola oil in the animal diet and muscle location

Twelve pigs at about 35 days of age were fed a control diet or test diets containing either 10% or 20% canola oil (CO) for 100 days. Four different muscles were excised from each carcass at 24 h post-mortem for analyses. Inclusion of 10% and 20% CO in the animal diet increased (P < 0·05) the relative amount (weight per cent) of unsaturated fatty acids in the total lipids (lipids extracted by 2:1 chloroform-methanol) by 6·7 and 15·8 percentage points, respectively, from 57·8% for the control and also increased (P < 0·05) that of polyunsaturated fatty acids by 5·5 and 9·7 percentage points, respectively, from 19·4% for the control. The 20% CO treatment increased (P < 0·05) the relative amount of monounsaturated fatty acids (primarily C18:1) by 6·1 percentage points from 38·4% for the control, while the 10% CO treatment had no significant effect. The 10% or 20% CO treatment had no significant effect on microsomal enzymic lipid peroxidation activity, heme pigment content, nonheme iron content and total lipid concentration. Overall lipid oxidation in ground muscle samples stored at 4°C tended to be higher for the 10% and 20% CO treatment groups than for the control. The tendency of increased lipid oxidation by the CO treatments apparently resulted from the increased percentages of polyunsaturated fatty acids, rather than from changes in catalytic constituents.     

Effect of dietary vitamin e on the oxidative stability of raw and cooked rabbit meat

The effect of dietary α-tocopheryl acetate supplementation (200mg/kg diet) on plasma and muscle levels of α-tocopherol and the oxidative stability of raw and cooked rabbit meat was determined. Two groups of 20 male hybrid rabbits were fed the experimental diets from 35 to 80 days of age. Feed intake, live weight, feed efficiency and qualitative traits of the carcass and meat were recorded. The α-tocopherol levels in plasma and muscle were significantly higher (p≤0·01) in the supplemented group, which also showed an increase in oxidative stability in both raw and cooked meat. The higher α-tocopherol level improved the physical traits of the meat, significantly reducing shear value and increasing water-holding capacity; n-3 fatty acids in raw and cooked meat increased (p≤0·05) and the thrombogenic index decreased (p≤0·05). Dietary vitamin E did not influence weight gain, feed intake and dressing yield.     

Lipid and fatty acid composition of rabbit meat: Part 1.-Apolar fraction

The apolar lipid contents and the fatty acid composition of meat from two rabbit breeds (New Zealand white and commercial hybrid HYLA) fed two commercial diets of different protein and crude fibre levels have been studied. The total and apolar lipid content of meat from both rabbit breeds ranged from 4·9 to 10·5% (wet weight). The individual lipid classes of the apolar fraction are described. Triglycerides accounted for more than 80% of total apolar lipids. The fat from rabbit meat is comparatively richer in palmitic acid (about 40% being always the major fatty acid), in linoleic acid and in myristic acid and poorer in stearic acid than other meats. Although differences in the fatty acid compositions of meat were observed, only clear influences of age, sex, breed, and/or feeding on the fatty acids C-16:0, C-18:0 and C-18:2 of total and apolar lipids were found.     

Performance of growing–fattening lambs fed whole cotton seed

Effects of diets containing increasing levels of whole cotton seed (WCS) on feed intake, liveweight gain, feed conversion, feeding margin and carcass characteristics were studied. Diets contained 0, 5, 10, 15, 20 and 30% WCS and were fed ad libitum to growing lambs for 54 days. All diets were approximately isonitrogenous (163–186 g crude protein kg⁻¹ dry matter) and isocaloric (19–20 MJ gross energy kg⁻¹ of dry matter). During the first 28 days, four groups of 10 Karagouniko male lambs with initial liveweights of approximately 17·6 kg were fed diets containing 0, 5, 10 and 15% WCS and then, for the next 26 days, diets containing 0, 10, 20 and 30% WCS, respectively. Lambs fed the 15–30% WCS diet ingested about 20 mg kg liveweight⁻¹ day⁻¹ of free gossypol. At 54 days and liveweights of approximately 34·7 kg, five lambs from each treatment were slaughtered and carcass data were collected. There were significant differences in feed intake, liveweight gain, cooler shrink, rumen contents, intestinal fat and liver weight among the lambs fed these diets. Cooler shrink and intestinal fat, and perirenal fat and the combined weight of intestinal and perirenal fat, were significantly (P < 0·05) correlated. Pelleting of the WCS diets reduced the concentration of free gossypol in these diets. It was concluded that WCS was satisfactory as a feed ingredient for growing sheep and can be incorporated into ruminant diets as a source of energy and protein. No indication of gossypol toxicity was detected. © 1998 Society of Chemical Industry     

Anatomical and joint dissection studies of tissue weight distribution in buffalo bulls and cows: Part 2-Fat partition and distribution

Six buffalo bulls and six buffalo cows were slaughtered between, respectively, 430-560 kg and 405-585 kg liveweight. Sex differences in fat partition and distribution were examined using one-way analyses of covariance on data converted to logarithms. Buffalo bulls and cows showed no significant differences in the partition of total body fat between the carcass and the offal or between the different components of the total carcass fat (subcutaneous, SCF; intermuscular, IMF; kidney and channel, KCF) and those of the total offal fat (caul; mesenteric; heart). In addition, no significant differences between bulls and cows were detected with respect to the partition of the entire side fat between its component depots (SCF; IMF; KCF) and the partition of the dissected side fat (DSF) between its elements (SCF; IMF). Bulls did not differ significantly from cows in the distribution of IMF between cuts. However, bulls had more of their total SCF in the buttock cuts (P < 0·05) and pistol (P < 0·001) and BLRC (P < 0·01) expensive cut groups, while cows had more weight of total SCF contained in the flank (P < 0·05) and the 7th-10th rib (P < 0·01). The weight of total DSF was greater (P < 0·05) in the buttocks of bulls and (P < 0·01) in the flanks of cows.     

Carcass characteristics and composition of Brahman, angus and Brahman x Angus steers fed for different times-on-feed

Twenty-five steers of each of three breedtypes (Angus, Brahman and F(1) Brahman x Angus) were sorted by frame size and muscle thickness, assigned to groups (five steers of each breedtype) to be fed for 0, 56, 112, 168 or 224 days, slaughtered and compared for various carcass traits. Steers of each breedtype had similar dressing percentages. Carcasses from all three breedtypes merited similar USDA quality and yield grades; breedtypes differences in quality grade were slight. Differences were found in the fat deposition patterns exhibited by the three breedtypes. Brahman steers tended to deposit more of their total fat as subcutaneous fat early in the feeding period. Angus steers had more (P < 0·05) seam fat as a percentage of carcass weight at all five feeding periods and more (P < 0·05) kidney, pelvic and heart fat at two of the five feeding periods than Brahman steers. Brahman steers had a higher percentage of their separable lean in the muscles of the round than did steers of the other breedtypes.     

Effect of diet on animal performance, lipid composition of subcutaneous adipose and liver tissue of beef cattle

Two trials were carried out with Brahman beef cattle to study animal performance and carcass characteristics as well as fatty acid composition of subcutaneous adipose and hepatic tissue, as influence by length of grain feeding period or a pasturing regimen. In trial 1, steers were allotted to three feedlot finishing periods (76, 104 and 146 days) after being backgrounded on pasture. Steers fed 76 days had greater average daily gains (P < 0·05) than steers fed 146 and 104 days, respectively. Carcasses of steers slaughtered after 146 days on feed had higher (P < 0·05) marbling scores, quality grades, fat over ribeye, quality yield and per cent kidney, pelvic and heart (KPH) fat than steers fed for 104 and 76 days. The proprortions of certain fatty acid of subcutaneous fat and liver tissue were influenced by the length of grain feeding. There was a marked increased in the proportion of oleic acid in both tissues as the steers remained longer in the feedlot and a higher percentage of total saturated fatty acids at 76 days than at the other two times. Quantitative separation of hepatic lipid classes by the Iatroscan revealed that phosphatidylcholine and phosphatidylethanolamine were the main components of the phospholipids. Presents as minor components were cardiolipin and sphingomyelin. No differences (P > 0.·05) in these individual subclasses of liver lipids or in triglycerides were observed between the feedlot groups. Liver polyunsaturated fatty acids (PUFA) were higher (P < 0·001) at 104 than 76 days. In trial 2, steers fed a concentrate diet gained faster (P < 0·05) than the pasture group after 138 days. Marbling scores, yield grade, quality grade, fat over ribeye and per cent KPH were higher (P < 0·01) for the concentrate group while fat color scores were higher (P < 0·01) for the pasture group. Liver fatty acid analysis of summed ω6 PUFAs of triglyceride, phosphatidylcholine, phosphatidylethanolamine were higher for the feedlot than the pasture group. Linoleic acid was higher (P < 0·05) in the TG and PC liver subclass of the feedlot animals while higher (P < 0·05) linolenic acid occurred in the pasture group.     

Performance of growing–fattening lambs fed diets containing different proportions of cotton seed meal

A lamb feedlot study was conducted to evaluate the nutritional value of cotton seed meal (CSM) as compared with that of sunflower meal as protein supplements for growing lambs. Forty-five Karagouniko male lambs immediately after weaning, having an average liveweight of approximately 14.7 kg, were assigned randomly to one of three growing lamb rations. CSM substituted for sunflower meal in a growing–finishing feedlot diet at levels of 0, 10 and 20% to provide 0, 50 and 100% of supplemental protein requirement, respectively. Diets were fed ad libitum and water was offered freely. All diets were approximately isonitrogenous and isocaloric. After being fed for 61 days and having reached a liveweight of approximately 27.6 kg, five lambs from each treatment were slaughtered and carcass data were collected. No significant differences (P > 0.05) in feed intake or the weight increase of lambs were found among groups given the 0, 10 and 20% treatments, indicating that lambs utilized CSM as effectively as sunflower meal when fed on an equal crude protein and crude fibre basis. The dressing percentage of the cold carcass, but not the warm carcass, and intestinal content weight were significantly influenced (P < 0.05) by the diet. Cooler shrink and intestinal fat, and perirenal fat and the combined weight of intestinal and perirenal fat were significantly (P < 0.05) correlated. Feeding margin was highest for the control diet, intermediate for the 10% CSM diet and lowest for the 20% CSM diet. It was concluded that CSM is accepted readily by growing sheep and can be incorporated into diets as a source of supplemental protein for growing–fattening lambs. No evidence of gossypol toxicity was noted. © 1999 Society of Chemical Industry     

Feedlot performance and carcass evaluation of heifers fed finishing diets as weanling calves or as yearlings

Twenty commercial Herefored, Angus and Hereford × Angus, weanling and yearling heifers from the same herd were compared for feedlot performance and certain carcass characteristics. Yearlings tended to gain weight more rapidly than did weanlings. Since the cattle were group-fed, no analyses of feed efficiency could be performed. Yearlings appeared, however, to require less feed per unit of gain. The cattle were slaughtered when live weight approached 443 kg. Weanlings were fatter; had more kidney, pelvic and heart fat; merited higher (less desirable) USDA yield grades; had more desirable USDA quality grades and higher dressing percentage (P<0·05) than did yearlings. Ribeye area was not different between treatments. Yearlings yielded a higher percentage of closely trimmed retail lean cuts than did weanlings (P < 0·05). Sensory panel scores were higher (more desirable) for weanlings than for yearlings for both ribeye and inside round steaks (P < 0·05), while no differences were identified for flavor, juiciness or overall palatability of steaks. Warner-Bratzler shear force data generally supported taste panel evaluations for tenderness. These data suggest that carcass composition is impacted by the way cattle are managed and refute the idea that cattle have the same body composition at a given weight regardless of age at slaughter or nutrient density of the diet during finishing.     

Evaluation of cotton seed cake as a feed ingredient for fattening sheep

The value of cotton seed cake as a source of crude protein in sheep diets was studied. The cotton seed cake was incorporated into diets at levels of 0, 15 and 30% after replacement of soya bean meal and was fed ad libitum to growing lambs. The diets were formulated to be isonitrogenous and isocaloric. Sixteen lambs (8 male and 8 female) having an average liveweight of approximately 13.6 kg were used in each treatment. After being fed for 62 days and having reached a liveweight of approximately 26.7 kg, five male lambs from each treatment were slaughtered and carcass data were collected. Results of the growth trial showed that there were no significant differences in feedlot performance or carcass analysis among the lambs fed these diets. The dressing percentage was slightly higher (P > 0.05) for lambs fed the 15% cotton seed cake compared with the 30% cotton seed cake and control diets. However, the final weights were substantially higher (P < 0.001) and live average daily gains and feed intakes were all higher (P < 0.10) for male animals. It was concluded that cotton seed cake is an acceptable feed ingredient for growing sheep and can satisfactorily replace soya bean meal as a source of protein in ruminant diets, a feedstuff locally produced in Greece and substantially cheaper than the imported soya bean meal.     

Manipulation of the fatty acid composition of pig meat lipids by dietary means

Pigmeat products have been associated with an unhealthy image due to the relative proportions of polyunsaturated and saturated fatty acids. The aim of this experiment was to improve the fatty acid profile of the carcass fat by feeding various dietary sources of fat. Groups of 10 female Large While × Landrace pigs were fed one of four experimental diets. Five in each group were slaughtered at 70 kg live weight and the remaining five at 100 kg live weight. The diets were offered ad libitum and daily intake was recorded. The diets were based on barley, soya bean meal and fishmeal. Diet 1 contained 50 g tallow kg^?1, a relatively saturated fat, and diets 2, 3 and 4 contained 50 g soya oil kg^?1, an unsaturated fat. Diet 3 also contained 7.5 g GLA oil kg^?1, which is rich in gamma linolenic acid, with the aim of increasing the production of arachidonic acid in the body fat. Diet 4 was supplemented with 9.5 g EPAnoil kg^?1, which is rich in eicosapentaenoic acid and docosahexaenoic acid. There were no significant differences between dietary treatments in performance (daily liveweight gain or the efficiency of food conversion to liveweight gain) of the pigs slaughtered at 70 kg live weight, but small differences were observed at 100 kg live weight, where pigs on treatments 2, 3 and 4 performed slightly better than those on treatment 1. At both slaughter weights the lipid content of the m semitendinosus was higher than that of the m longissimus dorsi (approximately 24 and 13 g kg^?1, respectively). The pattern of fatty acids in the dietary fat was reflected to varying degrees in the carcass fat. Diet 1 resulted in the highest levels of palmitic, palmitoleic, stearic and oleic acids whereas diets 2, 3 and 4 gave high levels of linoleic and linolenic acids. The extra gamma linolenic acid in diet 3 did not result in a consistently significant increase in the production of arachidonic acid. The supplement of EPAnoil gave significant increases in the levels of eicosapentaenoic and docosahexaenoic acids in the body lipids. The polyunsaturated to saturated fatty acid ratio of the body lipid was increased with diets 2, 3 and 4 to about 1.0. In spite of high levels of linoleic acid, there were no adverse effects during the processing of the carcasses and the taste panel evaluation did not reveal any treatment differences.     

Effect of the fattening diet on the development of the fatty acid profile in rabbits from weaning

The effect of the fattening diet on the intramuscular fatty acid composition was studied on a total of 96 hybrid rabbits. Animals were slaughtered at weaning, at 1.6 kg after the consumption for three weeks of various diets containing low (14.28%), medium (18.04%) and high (20.48%) fibre content, and at 2 and 2.30 kg after the consumption of a common non-medicated concentrate, as occurs commercially. Weight had an effect on the percentage of intramuscular fat that decreased as weight increased, as well as on the percentage of most fatty acids except for saturated fatty acids. The percentage of monounsaturated fatty acids increased from weaning whereas polyunsaturated fatty acids subsequently decreased due to a reduction of n-6 fatty acids. In general, diet affected the fatty acid profile in rabbits slaughtered at 1.6 kg, which the rabbits were having exclusively one of the three fattening diets. The finishing common diet seems to reduce most differences due to the growing diet which, if rich in fibre, would produce a more favourable final n-6/n-3 ratio.     

Meat production characteristics of Egyptian Baladi and Angora goats

Fifteen Baladi and 20 Angora intact males raised together from birth until 8 months of age were grown on a commercial concentrate mixture fed at the rate of 0·6 kg/head/day with chopped wheat straw fed at 0·5 kg/head/day for 14 weeks. Body measurements were taken before slaughter and carcass measurements and offal weights after it. The right sides of all carcasses were dissected into cuts, weighed and deboned. Fat was separated from the 9-10-11 rib joints and estimated. The two breeds did not significantly differ in birth weight, weaning weight, carcass weight, dressing percentage, most body measurements, all carcass measurements and most offal weights. Sigmificant differences were only found in body length, height at withers, weights of spleen and kidney fat. However, the Baladi had significant heavier loin and shoulder (P < 0·05) and breast and flank (P < 0·05) than the Angora which had heavier legs (P < 0·05). The carcasses of the two breeds had very similar percentage of edible meat (68·38 versus 68·65), lean (57·47 versus 57·38) and fat in the rib joint (10·91 versus 11·27).     

Dietary manipulation of the yield and composition of milk: Effects of dietary inclusions of barley and oats in untreated or formaldehyde-treated forms on milk fatty acid composition

Eight 1st-lactation cows were given four dietary treatments in a duplicated 4×4 Latin square experiment. Diets consisted of hay and soya bean meal together with barley, formaldehyde-treated barley, oats or formaldehydetreated oats (approximately 34:12:54 on a dry matter basis). Barley diets supplied 211 g fatty acids d^?1, oats diets supplied 537 g d^?1. The fatty acid composition (g kg^?1 total fatty acids) for barley diets was: 300 (16:0); 20 (18:0); 150 (18:1); 470 (18:2); 60 (18:3). Corresponding values for oats diets were 180, 20, 390, 380 and 30 g kg^?1. Formaldehyde treatment of the cereals tended to increase milk yield and reduce milk fat content (P<0·01 for barley) but did not affect milk fatty acid composition. Feeding oats in replacement for barley significantly (P<0·05) increased milk yield and lactose yield and reduced milk fat content (P<0·05 for the untreated cereals) and protein contents (P<0·01) without significant effects on milk fat or protein yields. Oats diets led to significant (P<0·001) reductions in the content of 8:0–16:0 fatty acids in milk fat with associated increases (P<0·001) in the content of 18:0 and 18:1. Changes in milk fat content of 18:2 and 18:3 acids were small. The results show the inclusion of oats in the cow's diet to be a means of reducing the saturated fatty acid content of milk fat thereby improving the nutritional value of milk and milk products and their appeal to the health-conscious consumer.     

The evaluation of liquefied de-oiled herring silage in diets for growing pigs: Feeding trials

Pens of pigs grown from 30 to 60 kg liveweight (LW) and 30 to 90 kg LW in separate experiments were fed diets containing either 75 or 150 kg t^?1 dietary dry matter of de-oiled herring offal silage stored for up to 8 weeks, and their performance compared with pens of pigs fed control diets based on soya bean meal formulated to contain equivalent levels of total lysine. All pens of pigs were rationed on the same time-based scale of feeding. Pigs in both weight ranges fed herring silage diets grew significantly faster than the control pigs; in the 30–60 kg LW range growth rates were 687 and 529 g day^?1 (P<0.01) and in the 30–90 kg LW range, 670 and 588 g day^?1 (P= 0.05), respectively. The mean feed: gain ratio was also better with pigs fed the herring silage diets. No significant differences were found between treatment and control pigs slaughtered at either 60 or 90 kg LW for back fat probe measurements or killingout percentage. No pigs were down graded by the Meat and Livestock Commission carcass quality classification.     

Morning versus afternoon cutting time of Berseem clover (Trifolium alexandrinum L.) affects feed intake, milk yield and composition in Girgentana goats

Twenty lactating Girgentana goats were used to evaluate the effect of morning v. afternoon cutting time of Berseem clover (Trifolium alexandrinum L.) on feed intake, milk yield and milk composition. Goats were randomly divided into two groups of ten animals, receiving 10 kg of fresh Berseem clover cut at 9.00 (AM group) or 16.00 (PM group), respectively; 500 g of concentrate was given individually to goats before offering forage. Feed intake increased (P<0·01) in the PM group (30·5 v. 25·3 g dry matter/kg body weight), associated with the different nutrient content of diets: lower crude protein but higher dry matter, neutral detergent fibre, water soluble carbohydrates (WSC) and total fatty acids in the PM-harvested forage. Milk production, protein and casein content were higher (P<0·05) in the PM group (1415 g/d, 3·25% and 2·42% v. 1277 g/d, 3·15% and 2·33%, respectively), whereas no differences between groups were detected for milk fat, lactose or urea content. Body weight slowly decreased from the start to the end of the experiment, without differences between groups. This study showed an important milk yield responses in Girgentana goats offered afternoon-cut compared with morning-cut Berseem clover, due to a marked increase in WSC in the afternoon-cut forage.     

Prediction of carcass composition in the rabbit

Carcass composition of two synthetic rabbit breeds was predicted from retail cuts and external measurements by using regression equations. Breed R has a higher adult weight and reaches slaughter weight 1 week before breed V. Sixty rabbits of each breed were slaughtered when they (approximately) reached the Spanish commercial liveweight of 2kg. The carcasses were measured and retailed according to the norms of the World Rabbit Scientific Association. Rabbit carcass composition is well defined by meat percentage of the commercial carcass and ratio meat bone . External measurements on the carcass, retail cuts and meat of retail cuts or muscular masses are all bad predictors of carcass meat percentage or ratio meat bone (R(2) < 0.53). The ratio meat bone of the hind leg can give reasonable predictions for carcass meat percentage and meat bone ratio (R(2) = 0.60 and 0.69). Dissectible carcass fat weight and dissectible carcass fat percentage can be predicted by the perirenal fat weight (R(2) = 0.77 and 0.69). Fat depots had a low predictive power for fat percentage of the dissected meat in the half carcass.     

Lipid and fatty acid composition of rabbit meat: Part 2.-Phospholipids

The phospholipid contents (and their fatty acid composition) of the meat of two rabbit breeds (New Zealand white and the commercial hybrid HYLA) fed with two commercial diets of different protein and fibre contents, have been determined. The phospholipid contents in the meat of both rabbit breeds ranged from 9% to 19% total lipid. In this fraction seven different phospholipid classes were detected but phosphatidylcholine (PC) and phosphatididylethanolamine (PE) had average percentages of 50 and 20 of the total phospholipids. The major fatty acids of both phosphatidylcholine and phosphatidylethanolamine were C-16:0, C-18:0, C-18:1 and C-18:2, these together representing more than 70% of the total fatty acids. In general, the PC had an higher saturated fatty acid content than PE, which had a lower percentage of C-16:0 but higher C-20:4. Although differences in the fatty acid composition of the phospholipid fractions of the rabbit meat were observed, the only clear influences of age, sex, breed, and/or feeding were found with the C-16:0, C-18:0 and C-18:2 fatty acids.     

Paris ham processing: Technological yield as affected by residual glycogen content of muscle

The aim of the present experiment was to study the relationships between pH, protein and residual glycogen content of pig muscle on the one hand, and technological yield (TY) of Paris ham processing on the other (Paris ham is a type of cured cooked ham). Fifty-two pigs were slaughtered at 100 kg liveweight in a commercial abattoir, in four slaughter series. Ultimate pH, protein and glycogen were determined around 24h post mortem. Two days after slaughter, the right hams were processed to Paris ham. Residual glycogen levels varied from 0 to 78 μmol/g of fresh tissue. All correlations between TY and the other traits under study were significant at the P < 0·05 level. Correlation between glycogen and TY was by far the highest one (r = 0t-0·60, P < 0·01). Protein content and both pH values gave similar but lower correlations with TY (r around 0·4, P < 0·01). It is concluded that the results of the present study agree with the hypothesis that the residual glycogen content of muscle has a direct effect on the technological yield of cooked ham processing.     

Characteristics of pork products from swine fed a high monounsaturated fat diet: Part 3-A high-fat cured product

Fresh pork bellies from animals fed a control sorghum-soybean diet and a similar diet containing 12% high-oleic sunflower oil (HOSO) were cured and processed in a smokehouse to an internal temperature of 55·6°C. Cooking losses were not significantly different (p < 0·05) between bacon strips from animals on the control diet and those from animals on the HOSO diet. The ratio of monounsaturated fatty acids to saturated fatty acids for the cooked rasher from the HOSO group was 1·84 times that for the cooked rasher from the control group (2·48 versus 1·35). The cooked rasher had a slightly lower (p < 0·05) percentage of total monosaturates that uncooked bacon strips within each diet group. When considering stearic acid as a fatty acid that does not raise the plasma cholesterol level in the human, along with all unsaturated fatty acids, only 16·83% and 12·26% of total fatty acids in the cooked rasher and the drip, respectively, from the HOSO group were fatty acids (C14:0 and C16:0) which may raise the plasma cholesterol level. The residual nitrite level in the raw and cooked bacon was higher (P < 0·05) for samples from the HOSO group than for those from the control group, probably due to binding of nitrite to the double bonds in unsaturated fatty acids that were higher for samples from the HOSO group. The extent of the accumulation of thiobarbituric acid-reactive substances during frozen storage was not affected (P > 0·05) by the inclusion of 12% HOSO in the animal diet, regardless of the packaging method.