Effects of dietary α-linolenic acid on the fatty acid composition, storage stability and sensory characteristics of pork loin

Sensory qualities markers of n-3 PUFA enriched fresh pork meat fattened by linseed oil and selenium methionine

This study revealed the differences of sensory markers between traditional pork meat, fatten by 3 % soybean oil, and n-3 PUFA enriched pork meat, which was fattened through a pig diet supplemented with 3 % linseed oil and a combination of 3 % linseed oil with 0.3 mg/kg of selenium methionine. E-nose (tongue) analysis indicated pronounced differences in odor and taste profiles of pork meats between control group and linseed oil treatment group. 1-octen-3-ol and 5'-IMP were identified as the volatile and non-volatile markers of n-3 PUFA enriched pork meat, respectively. The volatile marker 1-octen-3-ol was decreased, while the non-volatile marker of 5'-IMP was increased in n-3 PUFA enriched pork meat fattened by linseed oil, as compared to pork fattened by soybean oil. The supplement of 0.3 mg/kg of selenium methionine to 3 % linseed oil diet had no significant effect on 1-octen-3-ol, but mitigated the increase of 5'-IMP and enhanced the meat's cohesiveness.

Effect of Gut Microbiota on Blood Cholesterol: A Review on Mechanisms

The gut microbiota serves as a pivotal mediator between diet and human health. Emerging evidence has shown that the gut microbiota may play an important role in cholesterol metabolism. In this review, we delve into five possible mechanisms by which the gut microbiota may influence cholesterol metabolism: (1) the gut microbiota changes the ratio of free bile acids to conjugated bile acids, with the former being eliminated into feces and the latter being reabsorbed back into the liver; (2) the gut microbiota can ferment dietary fiber to produce short-chain fatty acids (SCFAs) which are absorbed and reach the liver where SCFAs inhibit cholesterol synthesis; (3) the gut microbiota can regulate the expression of some genes related to cholesterol metabolism through their metabolites; (4) the gut microbiota can convert cholesterol to coprostanol, with the latter having a very low absorption rate; and (5) the gut microbiota could reduce blood cholesterol by inhibiting the production of lipopolysaccharides (LPS), which increases cholesterol synthesis and raises blood cholesterol. In addition, this review will explore the natural constituents in foods with potential roles in cholesterol regulation, mainly through their interactions with the gut microbiota. These include polysaccharides, polyphenolic entities, polyunsaturated fatty acids, phytosterols, and dicaffeoylquinic acid. These findings will provide a scientific foundation for targeting hypercholesterolemia and cardiovascular diseases through the modulation of the gut microbiota.

Dietary supplementation with n-3 polyunsaturated fatty acids: Effects on reproductive and productive performance and meat quality in rabbit breeding

Rabbit breeding has many critical aspects related to reproduction, production, and animal welfare, which reduce its profitability as well as consumer attractiveness. Dietary supplementation with n-3 polyunsaturated fatty acids (PUFA) seems to be a good nutritional strategy to improve several aspects of rabbit breeding, enhance animal welfare and produce a new functional food considered healthy for human consumption. For this reason, the main available scientific research regarding the physiological effects of n-3 PUFA rich products supplemented to the rabbit diet will be reviewed. In particular, consequences on the reproductive performances of both doe and buck, the productive parameters, and the meat quality will be analysed.

Contents and composition of individual phospholipid classes from biceps femoris related to the rearing system in Iberian pig

During dry-cured ham processing, phospholipids (PL) are the main substrates of lipolysis and oxidation. However, the published data on individual PL classes in the pig muscle are inconsistent. This study determined the PL class contents and composition in biceps femoris of Iberian pigs according to the rearing system (Montanera vs Pienso). Phosphatidylcholine (PC), phosphatidylethanolamine (PE), cardiolipin (CL) and sphingomyelin contents were higher in the Montanera pigs than in the Pienso pigs. Total PL and PC, PE, phosphatidylinositol + phosphatidylserine and CL contained higher levels of oleic acid and slightly higher levels of n-3 polyunsaturated fatty acids (PUFA) but lower levels of n-6 PUFA in the Montanera pigs than in the Pienso pigs. The rearing system had no effect on the plasmalogen content but influenced aldehyde composition, mainly in PE and in total PL. These results can partially explain the differences in sensory properties of dry-cured ham between the Montanera and Pienso systems.

Current feeding strategies to improve pork intramuscular fat content and its nutritional quality

Pork, one of the most consumed meats worldwide, has been facing major challenges regarding its low sensory quality and unhealthy image of fat. This chapter addresses current feeding strategies to ameliorate pork sensory attributes and nutritional quality by increasing intramuscular fat deposition and improving fatty acid composition, respectively. Dietary protein reduction, alone or combined with some components, contributes to satisfy consumer requirements and enhances the competitiveness of the meat industry with higher pork quality and lower production costs. In addition, feeding sources of n-3 polyunsaturated fatty acids to pigs, mainly from marine origin (rich in eicosapentaenoic and docosahexaenoic acids), increases their content in pork, thus improving the health value of its fatty acid profile. In the near future, the inclusion of microalgae and seaweeds in feed represents a promising approach for the maintenance and development of the livestock sector, as an environmental friendly alternative to balance food and feed industries.

Unsaturated fat fraction from lard increases the oxidative stability of minced pork

Lard from pork back fat was dry fractionated based on crystallization temperature, resulting in fractions with a ratio of saturated to unsaturated fatty acids of 1.10 and 0.61. Lean minced pork was mixed with the saturated and unsaturated fat fraction and stored in modified atmosphere (80% O₂ and 20% CO₂) at 5 °C for 2, 5, 7, 9, and 12 days under light to investigate the effect on oxidative stability of lipids and proteins. The saturated fat group developed higher TBARS values and lower levels of free thiol groups during storage, indicating that the unsaturated fat fraction in minced pork promoted increased oxidative stability of both lipids and proteins. A higher content of α-tocopherol in the unsaturated fat fraction suggests that the differences in oxidative stability is causatively linked to the balance between the fatty acid composition and content of antioxidants. The TBARS values and free thiol content were negatively correlated, suggesting a relationship between lipid and protein oxidation.

Effect of diet and packaging system on the oxidative status and polyunsaturated fatty acid content of rabbit meat during retail display

The aim of this study was to evaluate the combined effect of two dietary lipid sources (sunflower vs. linseed oil) and three packaging methods (PVC film - BAG vs. modified atmosphere CO₂ 20% + 80% O₂ - MAP vs. and vacuum - VAC) on the oxidative status and polyunsaturated fatty acid content of rabbit loins (Longissimus thoracis et lumborum muscle), at days 1, 4 and 10 of simulated retail display. The diet, storage time and packaging method affected the oxidative status of rabbit meat under retail display. As expected, storage time, independently on the other factors, significantly reduced the antioxidant content of loin meat. Accordingly, TBARs values significantly increased during storage, as well as the dietary supplementation of linseed. The fatty acid profile of the fresh loin closely respected that of the diets. At day 10, oxidative status and fatty acid profile of MAP samples could be yet considered optimal.

Effects of dietary linseed on nutritional value and other quality aspects of pig muscle and adipose tissue

This study reports improvements in the nutritional value of pork by including linseed in the diets of boar and gilt pigs. Two feeding strategies, either short-term or long-term, were employed: (i) 0 g or 114 g linseed per kg of food provided to 16 pigs of 87 kg live weight for 20 or 27 days; (ii) 0 g, 10 g, 20 g or 30 g linseed per kg of food provided to 64 pigs of 46 kg live weight for 54, 62, 68 or 75 days. All diets were supplemented with DL-α-tocopheryl acetate (0•2 g/kg). The 18 : 3n-3 contents (18 : 2n-6 :18 : 3n-3 ratios in parentheses) of the short-term 0 g and 114 g/kg, and long-term 0g, 10 g, 20 g and 30 g/kg linseed diets, were 2•1 g (7•75), 28•1 g (0•70), 1•0 g (8•86), 3•4 g (2•73), 6•0 g (1•66) and 8•1 g/kg food (1•25) respectively. The long-term 30 g/kg diet reduced the n-6 : n-3 ratio of muscle and adipose tissue as successfully as the short-term 114 g/kg diet to accord with guidelines for the overall human diet (5 :1 or less) but required only 0•73 as much linseed and increased the proportion of C20-22 n-3 fatty acids more effectively; compared with their respective control diets, the 114 g/kg and 30 g/kg diets more than halved the n-6 : n-3 ratios in muscle to 3•8 and 3•9, approximately trebled the concentrations of 18 : 3n-3 in muscle to 0•43 mg and 0•28 mg/g tissue, and doubled the concentrations of 20: 5n-3 in muscle to 0•08 mg and 0•10 mg/g tissue. Similar changes occurred in adipose tissue. With both strategies, the majority of the changes had occurred by the time the first groups were slaughtered. There was a strong relationship between the 18 : 2n-6 :18 : 3n-3 ratio of the food and tissues and the accumulation of all C20-22 n-3 fatty acids, except 22 : 6n-3, which was unaffected by dietary linseed. The improvements in nutritional value were obtained without changes in organoleptic characteristics, as measured by a trained taste panel, or significant loss of shelf-life, as measured by TBARS analysis and colour stability.

Pork as a Source of Omega-3 (n-3) Fatty Acids

Pork is the most widely eaten meat in the world, but typical feeding practices give it a high omega-6 (n-6) to omega-3 (n-3) fatty acid ratio and make it a poor source of n-3 fatty acids. Feeding pigs n-3 fatty acids can increase their contents in pork, and in countries where label claims are permitted, claims can be met with limited feeding of n-3 fatty acid enrich feedstuffs, provided contributions of both fat and muscle are included in pork servings. Pork enriched with n-3 fatty acids is, however, not widely available. Producing and marketing n-3 fatty acid enriched pork requires regulatory approval, development costs, quality control costs, may increase production costs, and enriched pork has to be tracked to retail and sold for a premium. Mandatory labelling of the n-6/n-3 ratio and the n-3 fatty acid content of pork may help drive production of n-3 fatty acid enriched pork, and open the door to population-based disease prevention polices (i.e., food tax to provide incentives to improve production practices). A shift from the status-quo, however, will require stronger signals along the value chain indicating production of n-3 fatty acid enriched pork is an industry priority.

Long-chain polyunsaturated fatty acid sources and evaluation of their nutritional and functional properties

Recent studies have clearly shown the importance of polyunsaturated fatty acids (as essential fatty acids) and their nutritional value for human health. In this review, various sources, nutritional properties, and metabolism routes of long-chain polyunsaturated fatty acids (LC-PUFA) are introduced. Since the conversion efficiency of linoleic acid (LA) to arachidonic acid (AA) and also α-linolenic acid (ALA) to docosahexaenoic acid (DHA) and eicosatetraenoic acid (EPA) is low in humans, looking for the numerous sources of AA, EPA and EPA fatty acids. The sources include aquatic (fish, crustaceans, and mollusks), animal sources (meat, egg, and milk), plant sources including 20 plants, most of which were weeds having a good amount of LC-PUFA, fruits, herbs, and seeds; cyanobacteria; and microorganisms (bacteria, fungi, microalgae, and diatoms).

Effect of olive leaf (Olea europea L.) extracts on protein and lipid oxidation in cooked pork meat patties enriched with n-3 fatty acids

BACKGROUND

The effect of olive leaf extracts on lipid and protein oxidation of cooked pork patties refrigerated stored for 9 days was evaluated. Patties were prepared from longissimus dorsi muscle of pigs, and dietary supplemented with linseed oil.

RESULTS

Results showed that dietary linseed oil modified the fatty acid composition of pork patties by increasing (P ≤ 0.05) n-3 (α-linolenic acid) and decreasing (P ≤ 0.05) n-6 (linoleic acid) fatty acids. Olive leaf extracts at supplementation levels of 200 and, especially, of 300 mg gallic acid equivalents kg⁻¹ meat, delayed lipid oxidation by reducing (P ≤ 0.05) both primary (conjugated dienes and hydroperoxides) and secondary (malondialdehyde) oxidation products. They also inhibited protein oxidation in a concentration-dependent manner by reducing (P ≤ 0.05) protein carbonyls and increasing (P ≤ 0.05) protein sulfhydryls. In addition, they improved sensory attributes of the n-3 enriched patties.

CONCLUSION

Results suggested that olive leaf extracts might be useful to the meat industry as an efficient alternative to synthetic antioxidants.

Effects of feeding diets containing highly peroxidized distillers dried grains with solubles and increasing vitamin E levels to wean-finish pigs on growth performance, carcass characteristics, and pork fat composition

Lipid peroxidation in animal feed can negatively affect growth performance and meat quality. Weanling pigs (n = 432; BW = 6.6 ± 0.4 kg) were used to evaluate the effects of feeding peroxidized distillers dried grains with solubles (DDGS) with 3 levels of vitamin E (α-tocopheryl acetate) on growth performance, carcass composition, fatty acid composition of pork fat, and lipid peroxidation in LM. The DDGS source used in this study contained the highest thiobarbituric acid reactive substances (TBARS) value, peroxide value, and total S content (5.2 ng malondialdehyde/mg oil, 84.1 mEq/kg oil, and 0.95%, respectively) among 30 DDGS sources sampled. Pens within blocks were assigned randomly to 1 of 6 diets in a 2 × 3 factorial arrangement of treatments with 8 pens per treatment and 9 pigs per pen. Pigs were fed a corn-soybean meal (CON) or 30% peroxidized DDGS (Ox-DDGS) diets with 3 levels of vitamin E: none supplemented (No-E), NRC (1X-E), or 10X NRC (10X-E). Compared to CON, inclusion of 30% Ox-DDGS in diets reduced (P < 0.001) final BW (110 vs. 107 kg), overall ADG (0.76 vs. 0.74 kg/d), and G:F (0.39 vs. 0.37). Increasing dietary vitamin E concentrations improved G:F (P = 0.03) of pigs fed 10X-E and 1X-E vs. No-E diets (0.39 and 0.39 vs. 0.38, respectively). Hot carcass weight, dressing percentage, backfat depth, and LM area were reduced (P < 0.01) in pigs fed Ox-DDGS compared to CON, but percentage of fat-free carcass lean was not affected. Feeding Ox-DDGS increased (P < 0.001) PUFA concentration, particularly linoleic acid (P < 0.001), and iodine value (P < 0.001) in belly fat and backfat compared to pigs fed CON. Dietary vitamin E levels did not affect fatty acid profiles in belly or back fat. Loin muscle TBARS were measured to determine the lipid peroxidation level in pork loins. Although pigs were fed a Ox-DDGS source in this study, TBARS in LM were similar between Ox-DDGS and CON treatments. There was no interaction between Ox-DDGS and dietary vitamin E concentration in LM TBARS. Alpha-tocopherol concentration in LM was greater (P < 0.001) in 10X-E than No-E or 1X-E dietary treatments. Compared to CON, feeding Ox-DDGS increased α-tocopherol concentration in LM of pigs fed No-E (1.0 vs. 3.1 mg/kg; P = 0.005) but not in those fed 1X-E or 10X-E. These results indicate that feeding diets containing 30% Ox-DDGS to wean-finish pigs may negatively affect growth performance, but supplementation of additional vitamin E in the diet did not counteract these effects.

Effect of muscle type, packaging, and irradiation on lipid oxidation, volatile production, and color in raw pork patties

Effects of packaging and irradiation combinations on lipid oxidation, off-flavor, and color changes of raw patties prepared from three pork muscles were studied. Patties were prepared from each of the ground L. dorsi (L. thoracis and lumborum), psoas, and R. femoris muscles of pig, packaged either in oxygen permeable polyethylene bags or impermeable nylon/polyethylene bags, irradiated with an electron beam at 0 or 4.5 kGy dose, and then stored up to two weeks at 4 °C. Lipid 8 oxidation and color of the patties were determined after 0, 3, 7, and 14 days of storage, and volatiles 24 hr after irradiation. Irradiation and high fat content accelerated the lipid oxidation in raw meat during storage. Oxygen availability during storage, however, was more important than irradiation on the lipid oxidation and color values of raw patties. Irradiated meat produced more volatiles than nonirradiated patties, and the proportion of volatiles varied by the packaging-irradiation conditions of patties. Irradiation produced many unidentified volatiles that could be responsible for the off-odor in irradiated raw meat. No single volatile components but total volatiles, however, could be used to predict lipid oxidation status of raw meat.

Volatile profiles, lipid oxidation and sensory characteristics of irradiated meat from different animal species

Irradiated meats produced more volatiles and higher 2-thiobarbituric acid reactive substances (TBARS) than nonirradiated regardless of animal species. Irradiation not only produced many new volatiles not found in nonirradiated meats but also increased the amounts of some volatiles found in nonirradiated meats. The amounts of volatiles in aerobically packaged irradiated meats decreased with storage while those of nonirradiated meats increased. TBARS values were the highest in beef loin, followed by turkey breast and pork loin regardless of irradiation, packaging, and storage time. TBARS of meats showed positive correlation with total volatiles, but preference scores between irradiated and nonirradiated were similar.

Effect of dietary α-linolenic acid and vitamin E on the fatty acid composition, storage stability and sensory traits of rabbit meat

The synergistic effect of dietary linolenic acid and vitamin E on the oxidative stability and nutritional and eating characteristics of fresh and stored rabbit meat was studied. One-hundred hybrid male rabbits were divided into two homogenous groups and fed ad libitum two diets differing in the amount of sunflower and flaxseed and in the level of α-tocopherol, as follows: control diet: 0.08 kg kg(-1) sunflower, 50 mg kg(-1) α-tocopheryl-acetate and LNA-VE diet: 0.08 kg kg(-1) flaxseed, 200 mg kg(-1) α-tocopheryl-acetate. At 85 days, 20 rabbits per group were slaughtered and the thiobarbituric-acid reactive substances (TBA-RS), chemical composition, fatty acid profile and sensory quality were assessed on the longissimus dorsi muscles (fresh and stored for 8 days at 4 °C). The proximate composition of the fresh muscle was not significantly affected by the dietary treatment. Rabbits fed the LNA-VE diet showed a good capability to elongate and desaturate linolenic acid and this diet enriched the n-3 PUFA content of the meat without affecting its peroxidative stability. The sensory quality of the fresh and stored muscle was slightly affected by the dietary treatment, even though final tenderness (fresh meat) and overall acceptability (stored meat) of the LNA-VE rabbits showed significantly higher scores.

Lipid and protein oxidation of α-linolenic acid-enriched pork during refrigerated storage as influenced by diet supplementation with olive leaves (Olea europea L.) or α-tocopheryl acetate

The objective of this study was to evaluate the effect of diet supplementation with olive leaves or α-tocopheryl acetate on lipid and protein oxidation of raw and cooked n-3 enriched-pork during refrigerated storage. Enrichment of pork with α-linolenic acid through diet supplementation with linseed oil enhanced (p≤0.05) lipid oxidation in both raw and cooked chops but had no effect (p>0.05) on protein oxidation during refrigerated storage while decreasing (p≤0.05) the sensory attributes of cooked pork. Diet supplementation with olive leaves or α-tocopheryl acetate had no effect (p>0.05) on the fatty acid composition of pork but decreased (p≤0.05) lipid oxidation while exerting no effect (p>0.05) on protein oxidation in both raw and cooked α-linolenic acid-enriched chops stored and chilled for 9 days. Moreover, olive leaves and α-tocopheryl acetate supplemented at 10 g/kg and 200mg/kg diet, respectively, exerted (p≤0.05) a beneficial effect on the sensory attributes of cooked α-linolenic acid-enriched pork chops.

Oxidative stability in grinds from omega-3 enhanced pork

Juárez, M., Dugan, M. E. R., Larsen, I. L., Thacker, R., Rolland, D. C. and Aalhus, J. L. 2011. Oxidative stability in grinds from omega-3 enhanced pork. Can. J. Anim. Sci. 91: 623–634. In order to investigate the effect of enhancing n-3 fatty acid levels in carcasses on the retail and sensory characteristics of pork grinds, as well as the ability of increasing dietary levels of vitamin E to stabilize the increase in PUFA levels from flaxseed supplementation, 81 pigs were used in a 3×3 factorial experiment. Dietary treatments included three lengths of time (0, 3 and 6 wk) of flaxseed supplementation and three levels of vitamin E (40, 200 and 400 mg kg feed−1). α-Tocopherol tissue levels increased with dietary vitamin E supplementation (P<0.001), and fat softness (P=0.018) and total PUFA and n-3 fatty acids (P<0.001) increased with flaxseed supplementation. Most other animal performance, carcass and lean pork quality traits were not affected (P>0.05) by dietary treatments. In ground pork, the increase in TBARS after 6 d in retail was lower (P<0.001) with increasing dietary vitamin E levels. However, vitamin E had no effect (P>0.05) on the higher (P<0.001) TBARS levels observed in grinds from flaxseed fed pigs. The dietary addition of flaxseed negatively modified (P<0.05) all the sensory attributes of both cooked and reheated products. Increasing the fat content of the grinds up to 30% seemed to counteract (P>0.05) the negative effects of feeding flaxseed for 3 wk. Feeding vitamin E was not able to prevent negative effects (P<0.05) observed during retail display in grinds with either increasing fat content or higher n-3 fatty acids from dietary flaxseed. However, increasing dietary vitamin E only showed a protective effect (P<0.05) on retail appearance after long periods of ageing.

Increasing omega-3 levels through dietary co-extruded flaxseed supplementation negatively affects pork palatability

To clarify the impact of feeding co-extruded flaxseed on carcass quality and pork palatability, 96 pigs (48 barrows and 48 gilts) were fed three different levels of flaxseed (0%, 5% and 10% of dietary intake) for 76days. Carcass quality and meat quality characteristics of pure loin muscle and ground pork (20% fat) were evaluated. Fat hardness and belly firmness decreased (P<0.001) with increasing co-extruded flaxseed. Pigs fed co-extruded flaxseed levels had higher lean yield (P=0.045) and total lean content (P=0.034). Loin from barrows had higher fat content compared to gilts (P<0.001). Co-extruded flaxseed supplementation increased (P<0.001) omega-3 content in loin and ground pork. Pork flavour intensity and off-flavour intensity scores lowered (P<0.001) with increasing levels of co-extruded flaxseed, being more accentuated (P=0.023) in reheated pork chops from barrows. Diet affected all texture and flavour sensory characteristics (P<0.05) as tissue levels of omega-3 fatty acids increased, likely as a result of increased lipid oxidation.

Influence of extruded linseed on growth, carcass composition, and meat quality of slaughtered pigs at one hundred ten and one hundred sixty kilograms of liveweight

The Western diet is characterized by a high intake of SFA relative to PUFA, and the consumption of n-3 PUFA is decreased relative to n-6 PUFA. Therefore, there has been much interest in recent years in ways to manipulate the fatty acid composition of meat. The objective of this work was to determine the effects of dietary extruded linseed, an n-3 PUFA source, on growth performance, carcass composition, meat quality, and oxidative stability of pigs slaughtered at 111.0 (+/-4.8) kg of BW and 160.0 (+/-9.2) kg of BW. The association of these factors with BW at slaughter was also examined. Forty barrows, 78.1 (+/-1.75) kg of initial BW, were fed a control diet (2.5% sunflower oil) or a linseed diet containing 5% of whole extruded linseed. Both diets contained 170 mg of vitamin E and 250 mug of selenium. Eight pigs from each dietary treatment were slaughtered at 110 kg of BW and the others at 160 kg of BW. There was no dietary effect (P > 0.05) on growth, carcass characteristics, meat quality, or the activity of malic enzyme in LM and backfat. Inclusion of linseed increased (P < 0.05) n-3 PUFA content in both LM and backfat and decreased the n-6:n-3 PUFA ratio from 12 to 4.5 in LM, and from 11 to 3 in backfat. Liveweight at slaughter significantly influenced carcass characteristics, meat quality, total lipid and oxidative stability of LM, malic enzyme activity in adipose tissue, and fatty acid content of LM and backfat. This study shows that the inclusion of linseed in swine diets may improve the fatty acid profile of pork without deleteriously affecting oxidation or color stability. Thus, such a feeding practice may improve human health based on the n-6:n-3 PUFA ratio recommended for the human diet.

Effect of a high-linolenic acid diet on lipogenic enzyme activities, fatty acid composition, and meat quality in the growing pig

Forty-eight Duroc-cross gilts (40 kg initial BW) were fed a control or a linseed diet containing 60 g of whole crushed linseed/kg. Both diets were supplemented with 150 mg of vitamin E/kg. Eight pigs from each dietary treatment were slaughtered at 20, 60, or 100 d after the start of the experiment. There was no effect (P > 0.05) of diet on growth, carcass characteristics, or foreloin tissue composition. Feeding the linseed diet increased (P < 0.05) the content of n-3 PUFA in plasma, muscle, and adipose tissue, but docosahexaenoic acid was not (P > 0.05) altered by diet. The proportions of n-3 PUFA were highest (P < 0.01) in pigs fed the linseed-diet for 60 d, regardless of tissue (plasma, muscle, or adipose tissue) or lipid (neutral lipids and phospholipids) class. The linseed diet produced a PUFA:saturated fatty acid ratio > or = 0.4 in all groups and tissues, which is close to the recommended value for the entire diet of humans, as well as a robust decrease in the n-6:n-3 ratio. The decrease (P < 0.01) in the percentage of oleic acid in adipose tissue of pigs fed the linseed diet for 60 d could be attributed to a 40% decrease (P < 0.001) in stearoyl-CoA-desaturase activity. Diet did not (P > 0.05) affect the activities of acetyl-CoA-carboxylase, malic enzyme, or glucose-6-phosphate-dehydrogenase in any tissues. Muscle vitamin E content was decreased (P < 0.001) 30% in pigs fed crushed linseed for 60 d, whereas lower (P < 0.001) concentrations of skatole in pork fat were observed in linseed-fed pigs at all slaughter times. Inclusion of linseed (flaxseed) in swine diets is a valid method of improving the nutritional value of pork without deleteriously affecting organoleptic characteristics, oxidation, or color stability.

Safety assessment of DHA-rich microalgae from Schizochytrium sp. Part V: target animal safety/toxicity study in growing swine

The purpose of this study was to determine the potential toxicity of docosahexaenoic acid (DHA)-rich microalgae (DRM) from Schizochytrium sp., administered in the diet of growing swine. DRM was administered in the diet to groups of castrated male growing pigs (mixed commercial breeds, Landrace & Large White) reared from early weaned (weighing approximately 20 lbs) to approximately 250-270 lbs. Over the course of the 120 day study, animals were fed ad libitum four DRM treatment diets, each designed to optimize weight gain over the growing cycle, and a control diet. DRM was incorporated into the diet of the first treatment group at a level delivering 2.680 kg DRM per pig over the course of 120 days (a constant, whole-life exposure) equating to 598 g DHA per pig. DRM was incorporated into finisher diets only (administered over the last 42 days of the growing cycle) to treatment groups 2, 3, and 4 delivering 1.169, 3.391, and 5.746 kg DRM per pig (261, 756, and 1281 g DHA per pig). These levels represent approximately 1, 3, and 5 times the anticipated commercial dose and were delivered in a feeding strategy designed to mimic commercial use. Vitamin E was added to all diet groups to provide supplementary dietary antioxidant given the high content of polyunsaturated fat in DRM. There were no statistically significant treatment-related effects in clinical observations, body weights, food consumption, mortality, hematologic values, gross necropsy findings, organ weights or histopathology. The only DRM treatment-related changes were higher weight gain and feed conversion efficiency, anticipated results based on the increased fat content in the experimental DRM treatments. This study demonstrates that administration of DRM (at up to five times the anticipated commercial dose) did not produce any treatment-related adverse effects in commercial strains of swine.