Polyunsaturated Fatty Acids In Meat Research Articles

Effects of an essential oil blend rich in cinnamaldehyde and carvacrol on rumen biohydrogenation and fatty acid profile in the longissimus lumborum of growing lambs.

Essential oils extracted from cinnamon bark and oregano are rich in cinnamaldehyde and carvacrol and show potential for promoting animal performance. However, their impact on rumen biohydrogenation and the fatty acid composition of meat has not been reported. The hypothesis of this study was that a blend of essential oils rich in cinnamaldehyde and carvacrol would inhibit rumen biohydrogenation and promote the accumulation of polyunsaturated fatty acids (PUFAs) in lamb meat. The present study evaluated the effect of a blend essential oil (EO) rich in cinnamaldehyde and carvacrol on the nutrient digestibility, rumen biohydrogenation, growth performance, and fatty acid profile of the longissimus lumborum of lambs. Sixty male lambs with an average age of 84 ± 0.98 days and initial body mass of 25.4 ± 0.29 kg (mean ± standard deviation) were assigned randomly to four diets, and supplemented with 0 (EO0), 30 (EO30), 60 (EO60), and 120 (EO120) mg kg-1 dry matter of EO for 60 days. Although dry matter and neutral detergent fiber digestibility all showed a linear decrease (P ≤ 0.02) with increasing quantities of EO, final body mass and average daily gain increased linearly (P = 0.04), and average daily weight gain (ADG)/dry matter intake (DMI) tended to increase linearly (P = 0.07). Increasing EO supplementation resulted in a linear decrease in total volatile fatty acid concentration, acetate molar percentage, and acetate-to-propionate ratio (P ≤ 0.03), with the EO120 treatment being lower than the other EO treatments (P ≤ 0.05). Seven lambs from the EO120 treatment and seven lambs from the EO0 treatment were randomly slaughtered. It was observed that the proportions of C18:2n6c and PUFA in longissimus lumborum were higher in the EO120 treatment than the EO0 treatment (P ≤ 0.05). The relative abundance of Firmicutes in the rumen was decreased by the EO120 treatment in comparison with the EO0 treatment (P ≤ 0.05). Furthermore, the predicted relative abundances of genes encoding for conjugated linoleic acid reductase tended to decrease with the EO120 treatment (P = 0.06). We demonstrated that supplementation of the EO blend rich in cinnamaldehyde and carvacrol can enhance lamb growth performance and promote the deposition of desirable PUFAs in meat. © 2024 Society of Chemical Industry.

A mixture of free and microencapsulated essential oils combined with turmeric and tannin in the diet of cattle in the growing and finishing phase: A new tool to enhance productivity

The study was conducted to evaluate whether adding a blend containing free and microencapsulated essential oils, combined with turmeric and tannin, can replace monensin as a performance improver, positively influencing animal health and meat quality. Fourteen male cattle with an average initial body weight of 253 kg and ten females with an average initial body weight of 239 kg were included in the experiment in a confinement system. The animals were divided into four independent groups: Males (M-PHYTO, inclusion of the phytogenic mixture; M-MONEN, inclusion of monensin); Females (F-PHYTO, inclusion of phytogenic; F-MONEN, inclusion of monensin). The diets were formulated for an average daily gain of 1.5 kg, with food provided twice daily. Data and biological samples were collected on days 33, 100, and 153. M-PHYTO and F-PHYTO showed greater average daily gain and body weight, with a tendency to consume more dry matter and feed efficiency. However, the apparent digestibility of nutrients was higher in animals in the MONEN group than those in the PHYTO group, regardless of sex. The total number of leukocytes in cattle in the M-PHYTO and F-PHYTO groups was higher due to the higher lymphocyte count in the blood of these animals. The activity of gamma-glutamyltransferase and aspartate aminotransferase in animals that consumed the phytogenic mixture was lower compared to animals that consumed monensin. TBARS levels were lower in the serum and meat of cattle in the M-PHYTO and F-PHYTO groups, as were the total thiol concentration and glutathione S-transferase activity in the blood and meat of these animals. Bacterial activity was greater in the rumen fluid of cattle that consumed the phytogenic, as demonstrated by the methylene blue reduction test. The total production of short-chain fatty acids and acetic acid showed an interaction between treatment and days for both sex classes and an effect of treatment for females, with a higher concentration in the rumen in the M-PHYTO and F-PHYTO groups. Propionic acid affected treatment and the treatment x day interaction for males and females, with the M-PHYTO and F-PHYTO groups showing higher concentrations. There was an interaction between treatment and day in the acetate/propionate ratio, being lower in M-PHYTO and F-PHYTO cattle. Treatment between ruminal microbiota groups had no effect. The rib eye area had more significant gains when consumed phytogenic by males and females. The subcutaneous and sirloin fat thickness was greater in F-PHYTO animals than in the control group; however, in males, the result was the opposite. The sum of polyunsaturated fatty acids in meat was higher in M-PHYTO compared to M-MONEN and lower in F-PHYTO meat compared to F-MONEN. These results indicate that the phytogenic mixture is a potential performance improver in the diet of growing and finishing cattle, regardless of sex, but meat characteristics differ between males and females.

Development of a new hyperspectral imaging technology with autoencoder-assisted generative adversarial network for predicting the content of polyunsaturated fatty acids in red meat

The establishment of a comprehensive predictive model for red meat polyunsaturated fatty acids holds profound significance for the food industry. However, challenges, such as intricate features and low chemical content bestow complexity upon this endeavor. In the study, an autoencoder-assisted generative adversarial network (AE-GAN) was used to address the intricacies of generative models in regression operations. Following numerous iterations, the AE-GAN generated samples akin to the original data. Upon the incorporation of these generated samples into training, the test set R2 values of Support Vector Regression, Random Forest and Fully Convolutional Network witnessed respective enhancements of 0.1589, 0.1482 and 0.2998. The outcomes underscore the efficacy of this novel approach in ameliorating the challenges faced by generative models in regression tasks, thereby augmenting the model's generalizability.

Antioxidant action of yerba mate on carcass and meat characteristics and fatty acid profile in meat and fat of lambs finished in tropical pastures

The objective was to evaluate the effect of the supplementation with natural antioxidants from Yerba mate (Ilex paraguariensis St. Hil.) on the performance, carcass and meat characteristics, and fatty acid profile in meat and fat of Texel × Ile de France lambs kept in Brachiaria-grass pasture. Twenty lambs with a mean age of 90days and 26.3kg of BW were distributed in a completely randomized design in two treatments with 10 replicates/treatment: Control-protein-energy supplement based on corn and soybean meal (150g/kg DM of crude protein) without the addition of natural antioxidant yerba mate and Yerba Mate - energy protein supplement with the addition of yerba mate (110g/kg DM). There was no treatment effect on animal performance and carcass characteristics. The subcutaneous fat thickness was significantly higher for lambs treated without yerba mate. There was no effect of nutritional treatments on the oxidative markers of lamb meat. The muscle of the animals treated with yerba mate showed a higher concentration of unsaturated and polyunsaturated fatty acids elaidic, linolenic, thymnodonic, docosadienoic, and ceorvonic. The fat of the animals treated with yerba mate showed a higher concentration of palmitoleic acid, linoelaidic acid, heneicosanoic acid, dihomo-γ-linolenic acid, and arachidonic acid. The concentration of polyunsaturated fatty acids was significantly higher in meat and fat of lambs treated with yerba mate. Including yerba mate in the diet of lambs kept on Brachiaria pastures improves the lipid profile of polyunsaturated fatty acids in meat and fat, without altering the performance of the animals.

Analysis of meat color, meat tenderness and fatty acid composition of meat in second filial hybrid offspring of MSTN mutant pigs

The objective of this study was to assess the meat quality in second filial hybrid offspring of MSTN−/− cloning boars × Chinese Bama sows with initial mean body weight of 90.52 ± 0.68 kg. Compared with wild-type pigs, the feed utilization rate of MSTN−/− pigs showed an increasing trend (adjusted P = 0.06), loin eye area of MSTN−/− and MSTN+/− pigs increased (adjusted P < 0.01) and thickness of subcutaneous fat decreased (adjusted P < 0.01), the proportion of polyunsaturated fatty acids in meat of MSTN−/− pigs increased (adjusted P < 0.05). By means of histochemical staining, immunofluorescence, scanning electron microscopy, qRT-PCR and WB technologies, it was verified that the decreased meat color score of MSTN−/− pigs was related to the increase of type IIB muscle fiber, and the increased pork tenderness was related to the decrease of collagen content. Overall, this research provides reference for the further utilization of MSTN gene mutant pigs.

Effect of Dietary Anthocyanin-Extracted Residue on Meat Oxidation and Fatty Acid Profile of Male Dairy Cattle.

Simple SummaryResidue produced by the extraction of anthocyanin from black rice and purple corn contains anthocyanins and phenolic acids. Several researchers have found that anthocyanins and phenolic acids have antioxidant functions in animals. Moreover, black rice and purple extracts have been reported as antioxidants in meat and meat products. However, the effects of anthocyanin-extracted residue (AER) from black rice and purple corn as animal feed on the fatty acid profile and oxidation of meat are still unknown. Therefore, the aim of this study was to investigate the effects of the inclusion level of AER in cattle diet on meat fatty acids’ profile and meat oxidation during storage. Our results showed that AER in cattle diet reduced the oxidation of lipid and protein of meat and had better red color stability during storage. In addition, it could improve concentration of n-3 polyunsaturated fatty acids (PUFA). In summary, AER in the feed of cattle could reduce meat oxidation leading to the extension of the shelf life of meat. Moreover, meat from cattle-fed AER had higher n-3 PUFA, which indicates healthier meat for consumers.This research aimed to evaluate the effects of anthocyanin-extracted residue (AER) in the diet of cattle on meat oxidation during storage and on the fatty acid profiles of the meat. Sixteen male dairy cattle (average body weight 160 ± 10.6 kg) were allotted to feed in a completely randomized design (CRD) with four levels of AER supplementation, 0, 20, 40, and 60 g/kg dry matter (DM) in the total mixed ration (TMR). These TMR diets were fed ad libitum to the cattle throughout the trial. At the end of the feeding trial (125 days), all cattle were slaughtered and meat samples from the Longissimus dorsi (LD) muscle were collected to assess meat oxidation and fatty acid profile. The antioxidant effect of AER on meat oxidation was investigated during 14 days of storage based on color, myoglobin redox forms, lipid, and protein oxidation. The results showed meat from cattle fed AER had better color stability, lower oxidation of lipid, protein and myoglobin than did meat from cattle fed the control diet (0 g/kg AER). Furthermore, fatty acid profiles were affected by AER supplementation with an increase in the concentration of n-3 polyunsaturated fatty acids (PUFA). These results support the inclusion of AER supplementation as a natural antioxidant in cattle to reduce meat oxidation and increase PUFA in meat.

Effect of Broussonetia papyrifera L. silage on blood biochemical parameters, growth performance, meat amino acids and fatty acids compositions in beef cattle.

ObjectiveThe study was conducted to investigate the effects of Broussonetia papyrifera L. (B. papyrifera) silage on growth performance, serum biochemical parameters, meat quality, and meat amino acids and fatty acids compositions in beef cattle.MethodsSixty-four male Angus beef cattle were assigned to 4 groups with 4 pens in each group and 4 beef cattle in each pen, and fed with the total mixed ration supplemented with 0%, 5%, 10%, or 15% B. papyrifera silage for 100 days (control group, 5% group, 10% group and 15% group) separately.ResultsBeef cattle had significantly higher final body weight (BW) in 15% group, higher average daily gain (ADG) and dry matter intake (DMI) in 5% group, 10% group and 15% group, and higher feed conversion ratio (FCR) in 10% group and 15% group. Significantly higher blood superoxide dismutase (SOD) concentration was noted in 15% group, higher blood total antioxidant capacity (TAC) in 10% group and 15% group, lower 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) in 15% group. Meat had lower pH in 15% group, higher Commission International DeI’Eclairage (CIE) L* in 5% group, 10% group, and 15% group, and lower drip loss in 15% group. Greater concentration of meat polyunsaturated fatty acids (PUFA) was observed in 10% group and 15% group, and docosahexaenoic acid (DHA) in 15% group.ConclusionDiet with 15% B. papyrifera silage could improve performance and increase final BW, ADG, DMI, and FCR, enhance the antioxidant functions by decreasing blood 8-OHdG and MDA and increasing blood SOD and TAC, improve the meat quality by lowing pH and drip loss and increasing CIE L*, increase the meat PUFA and DHA concentration. Polyphenols and flavonoids might be the main components responsible for the antioxidant activity and anti-biohydrogenation in the B. papyrifera silage. And B. papyrifera silage could be used as a new feedstuff in beef cattle nutrition.

Performance, fatty acids profile and oxidative stability of meat of rabbits fed different lipid sources

Abstract To evaluate the use of different lipid sources in diets of growing rabbits, 60 New Zealand White rabbits were evaluated on performance, carcass traits, meat composition, fatty acid profile and oxidative stability of refrigerated and frozen meat. The experiment was distributed in a randomized block design, in five treatments, with six replicates and two animals per experimental unit (one male and one female). The treatments consisted of five isonutritive diets, with 2.5% soybean oil (SO), sunflower oil (SFO), cottonseed oil (CO), beef tallow (BT) and poultry fat (PF). There was no effect (P > 0.05) of dietary lipid sources on animal performance, carcass traits and meat composition (P > 0.05). Dietary inclusion of beef tallow resulted in a lower proportion of polyunsaturated fatty acids in meat compared to vegetable oils. The values of thiobarbituric acid-reactive substances (TBARS) indicated higher oxidation in the frozen meat of the animals fed with sunflower oil, cottonseed oil and bovine tallow in their diets. In conclusion, vegetable oils and animal fats can be included in growing rabbit diets without impair performance and meat quality parameters. Dietary inclusion of soybean oil is more advantageous because it promotes the incorporation of polyunsaturated fatty acids and greater lipid stability of refrigerated and frozen rabbit meat.

Volatile flavor constituents in the pork broth of black-pig

Pork of black-pig in China is well known for its quality and preferred by consumers. However, there is a lack of research on its flavors. By solvent assisted flavor evaporation combined with GC-MS, 104 volatile compounds in the stewed pork broth of black-pig were identified with the dominant amounts of fatty acids, alcohols, and esters. By aroma extract dilution analysis-GC-O method, 27 odor-active compounds were characterized, including 2-methyl-3-furanthiol, 3-(methylthio)propanal, 2-furfurylthiol, γ-decalactone, nonanal, (E)-2-nonenal, and (E,E)-2,4-decadienal that had high FD factors. Compared to the common white-pig, the aroma compounds in both pork broths were almost the same, but the aroma profile of potent odorants for the black-pig pork broth showed less fatty and more roasted notes, which were partially attributed to the higher monounsaturated fatty acids and lower polyunsaturated fatty acids in meat. With aid of authentic chemicals and selected reaction monitoring mode of GC-MS/MS, 19 aroma compounds were quantitated.

Beef quality of young Angus × Nellore cattle supplemented with rumen-protected lipids during rearing and fatting periods

This work evaluated the beef quality parameters of 108 bulls randomly administered to three treatments during rearing in pastures and two treatments during fatting in feedlots, including mineral and rumen-protected lipids. Meat and fat color, cooking yield, shear force, sensorial traits and chemical and fatty acid compositions were evaluated. Generally, the beef quality parameters were not affected by the rumen protected lipids; however, supplementation with rumen-protected lipids during the rearing period yielded darker beef and brighter fat and increased beef tenderness in meat aged for 28days compared to the meat from animals that received only mineral supplementation. In addition, the percent of meat polyunsaturated fatty acids was negatively affected by the inclusion of protected lipids, yielding 5.58 and 3.72% in animals fed with and without rumen-protected lipids, respectively, during the fatting period.

The high-level accumulation of n-3 polyunsaturated fatty acids in transgenic pigs harboring the n-3 fatty acid desaturase gene from Caenorhabditis briggsae

Livestock meat is generally low in n-3 polyunsaturated fatty acids (PUFAs), which are beneficial to human health. An alternative approach to increasing the levels of n-3 PUFAs in meat is to generate transgenic livestock animals. In this study, we describe the generation of cloned pigs that express the cbr-fat-1 gene from Caenorhabditis briggsae, encoding an n-3 fatty acid desaturase. Analysis of fatty acids demonstrated that the cbr-fat-1 transgenic pigs produced high levels of n-3 fatty acids from n-6 analogs; consequently, a significantly reduced ratio of n-6/n-3 fatty acids was observed. We demonstrated that the n-3 desaturase gene from C. briggsae was functionally expressed, and had a significant effect on the fatty acid composition of the transgenic pigs, which may allow the production of pork enriched in n-3 PUFAs.

Sheep meat polyunsaturated fatty acids and human health in relation to recent nutritional guidelines

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Cholesterol and Lipid Peroxides in Animal Products and Health Implications - A Review

Cholesterol and Lipid Peroxides in Animal Products and Health Implications - A ReviewThe level of oxysterols in animal products depends on the temperature used in food processing, duration of heating, and storage time and conditions. High temperature, oxygen, exposure to light, chemical composition of the product and low level of antioxidants accelerate the formation of cholesterol oxidation products (COPs). Also the high content of polyunsaturated fatty acids in meat and eggs favours the formation of oxysterols. Dairy products are characterized by the lowest content of COPs of all animal products. The most common oxysterols present in products of animal origin are 7-ketocholesterol, 20α-hydroxycholesterol, 25-hydroxycholesterol and α, β-epoxycholesterol. Numerous studies have confirmed the adverse effects of COPs on animal and human health. They exhibit mutagenic, carcinogenic, angiogenic and toxic action, damage cell membranes, and inhibit cholesterol biosynthesis. The use of certain antioxidants in animal nutrition limits the formation of COPs during technological processing of meat, eggs and milk, as well as during storage of fresh products. The excessive oxidation of cholesterol can be additionally prevented through the use of appropriate packaging that limits oxygen and light exposure.

Fatty acid composition of minced meat, longissimus muscle and omental fat from Small East African goats finished on different levels of concentrate supplementation

Effects of supplementing Small East African (SEA) goats with concentrate diets on fatty acids composition of minced meat, M. longissimus dorsi (LD) and omental fat were assessed using 23 animals (14.5 months old and 20.1 kg body weight). Goats were subjected to four levels of concentrate supplementation: ad libitum concentrate allowance (T100), 66% (T66), 33% (T33) and 0% (T0) of ad libitum concentrate allowance. All goats were slaughtered after 90 days of experimental period. Minced meat from concentrate-supplemented goats had higher (P<0.05) proportions of unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA) and desirable fatty acid (DFA) than that of non-supplemented ones (T0). Minced meat from T00 and T66 goats had similar proportions of polyunsaturated fatty acids (PUFA) and n-6 PUFA that were higher (P<0.05) than that of other dietary groups. There was limited variation in fatty acids composition of LD attributable to concentrate supplementation. Trans-vaccenic and linoleic acids were in higher (P<0.05) proportion in omental fat from concentrate-supplemented goats whereas margaric and arachidonic acids were in higher (P<0.05) proportion in omental fat from non-supplemented goats. Overall, LD was associated with PUFA, omental fat with saturated fatty acids (SFA), minced meat with MUFA. It is concluded that finishing SEA goats on concentrate diets will increase the proportion of DFA in meat from them. In addition, the proportion of PUFA in meat from such goats will peak at concentrate supplementation equivalent to 66% of their ad libitum intake. Consumers should avoid high intake of internal fat due to their richness in SFA.

The effect of dietary linseed oils with different fatty acid pattern on the content of fatty acids in chicken meat

Effects of 1, 3, 5 or 7% of linseed oil in the diet on the content of fatty acids in breast and thigh meat were studied in broiler chickens. Oils made either of seeds of the linseed cultivar Atalante (A) with a high content of &amp;alpha;-linolenic acid or of the cultivar Lola (L) with a predominating content of linoleic acid were fed from 25 to 40 days of age. When feeding A, the contents of all n-3 polyunsaturated fatty acids (PUFA), including eicosatrienoic acid, were significantly higher, those of n-6 PUFA were lower, and the ratio of n-6/n-3 PUFA was narrower (&lt;I&gt;P&lt;/I&gt; &lt; 0.001) than when L was fed. The narrowest n-6 to n-3 PUFA ratio was observed at the content 36 g of &amp;alpha;-linolenic acid (58 g A) per kg of the diet while the widest one at 2 g of &amp;alpha;-linolenic acid (70 g L) per kg of the diet. When using L, the increasing level of linoleic acid in feed was associated with significantly increasing levels of all n-6 PUFA in meat. The content of all n-3 PUFA increased after the application of oil A, but the dependence for eicosapentaenoic acid in thigh meat was expressed significantly more precisely by the second degree parabola with the maximum at the level of 37 mg of &amp;alpha;-linolenic acid and for clupanodonic and docosahexaenoic acids by parabolas with maxima at the level of &amp;alpha;-linolenic acid in the diet 41 g and 30 g for breast meat and 35 g and 27 g for thigh meat, respectively. By means of the inclusion of linseed oil with a high content of &amp;alpha;-linolenic acid in the feed mixture it would be possible to produce poultry meat with a high content of n-3 PUFA as a functional food.

Poultry meat production as a functional food with a voluntary n-6 and n-3 polyunsaturated fatty acids ratio

We studied the effect of different levels of linseed oils made either of the flax cultivar Atalante with a high content of &amp;alpha;-linolenic acid (612 g/kg) or of the cultivar Lola with a predominating content of linoleic acid (708 g/kg) in a chicken diet upon the fatty acid pattern in meat. Cockerels Ross 308 were fed the diets containing 1, 3, 5 or 7 per cent of oil in the last 15 days of fattening. Breast meat (BM) and thigh meat (TM) without skin of 8 chickens from each dietary group were used for analyses. The relative proportions of fatty acids were expressed as percentages of total determined fatty acids. When feeding Atalante oil, the proportions of n-6 fatty acids were highly significantly lower while those of n-3 fatty acids were higher; the ratio of n-6/n-3 polyunsaturated fatty acids in meat was narrower (&lt;i&gt;P&lt;/i&gt; &lt; 0.001) than in chickens fed oil with a low content of &amp;alpha;-linolenic acid. In BM and TM, the relative proportions of &amp;alpha;-linolenic and &amp;gamma;-linolenic acids were nearly the same, the proportion of linoleic acid in BM was lower, and the proportions of the other polyunsaturated fatty acids in BM were higher than in TM. In BM, the ratio of n-6/n-3 polyunsaturated fatty acids was significantly (&lt;i&gt;P&lt;/i&gt; &lt; 0.001) more favourable than that found in TM. The relative proportions of total saturated and monounsaturated fatty acids in meat decreased and those of polyunsaturated fatty acids increased significantly (&lt;i&gt;P&lt;/i&gt; &lt; 0.01) in dependence on the increasing level of dietary oils. When feeding Atalante oil, a significant increase in the proportion of linoleic acid in BM but not in TM was observed. The proportions of the other n-6 fatty acids decreased and those of all determined n-3 fatty acids, with the exception of docosahexaenoic acid, significantly increased with the increasing level of oil in the diet. When feeding Lola oil, its increasing content in the diet increased the relative proportion of linoleic acid as well as its elongation to &amp;gamma;-linolenic acid; however, the proportions of arachidonic and adrenic acid did not change significantly (&lt;i&gt;P&lt;/i&gt; &gt; 0.05). The proportion of &amp;alpha;-linolenic acid increased in both BM and TM. The proportion of eicosapentaenoic and clupanodonic acids in BM significantly decreased. The ratio of n-6 to n-3 polyunsaturated fatty acids ranged from 0.9 to 13.6 and from 1.0 to 17.2 in BM and TM, respectively. An increase in the level of Lola oil in the diet by 1% caused that the n-6/n-3 polyunsaturated fatty acid ratio extended by 1.00 and 1.19 units in BM and TM, respectively. Dependences of n-6/n-3 ratio on the level of Atalante oil were expressed by equations of convex parabolas with minima at the level of oil 5.8 and 5.9% for BM and TM, respectively. By means of the inclusion of linseed oil with a high content of &amp;alpha;-linolenic acid in the feed mixture it would be possible to produce poultry meat as a functional food with a very narrow ratio of n-6/n-3 polyunsaturated fatty acids.

Metabolism of polyunsaturated fatty acids and their toxicity to the microflora of the rumen

Ruminal microorganisms hydrogenate polyunsaturated fatty acids (PUFA) present in forages and thereby restrict the availability of health-promoting PUFA in meat and milk. The aim of this study was to investigate PUFA metabolism and the influence of PUFA on members of the ruminal microflora. Eleven of 26 predominant species of ruminal bacteria metabolised linoleic acid (LA; cis-9,cis-12-18:2) substantially. The most common product was vaccenic acid (trans-11-18:1), produced by species related to Butyrivibrio fibrisolvens. alpha-Linolenic acid (LNA; cis-9,cis-12,cis-15-18:3) was metabolised mostly by the same species. The fish oil fatty acids, eicosapentaenoic acid (EPA; 20:5(n - 3)) and docosahexaenoic acid (DHA; 22:6(n - 3)) were not metabolised. Cellulolytic bacteria did not grow in the presence of any PUFA at 50 microg ml(-1), nor did some butyrate-producing bacteria, including the stearate producer Clostridium proteoclasticum, Butyrivibrio hungatei and Eubacterium ruminantium. Toxicity to growth was ranked EPA > DHA > LNA > LA. Cell integrity, as measured using propidium iodide, was damaged by LA in all 26 bacteria, but to different extents. Correlations between its effects on growth and apparent effects on cell integrity in different bacteria were low. Combined effects of LA and sodium lactate in E. ruminantium and C. proteoclasticum indicated that LA toxicity is linked to metabolism in butyrate-producing bacteria. PUFA also inhibited the growth of the cellulolytic ruminal fungi, with Neocallimastix frontalis producing small amounts of cis-9,trans-11-18:2 (CLA) from LA. Thus, while dietary PUFA might be useful in suppressing the numbers of biohydrogenating ruminal bacteria, particularly C. proteoclasticum, care should be taken to avoid unwanted effects in suppressing cellulolysis.

Effect of irradiation and packaging conditions after cooking on the formation of cholesterol and lipid oxidation products in meats during storage

The effect of irradiation and packaging conditions on the content of cholesterol oxidation products (COPs) and lipid oxidation in cooked turkey, beef, and pork during storage was studied. Ground turkey leg, beef, and pork were cooked, packaged either in oxygen-permeable or oxygen-impermeable bags, and irradiated at 0 or 4.5 kGy. Lipid oxidation and COPs were determined after 0 and 7 days of storage at 4°C. Packaging of cooked meat was more important than irradiation in developing COPs and lipid oxidation in cooked meats during storage. 7α-Hydroxycholesterol, 7β-hydroxycholesterol, β-epoxide, and 7-ketocholesterol were among the major COPs formed in cooked turkey, beef, and pork after storage, and their amounts increased dramatically during the 7-day storage in aerobic conditions. Irradiation had no significant effect on the amounts of any of the COPs found in cooked turkey and beef, but increased ( P<0.05) the amounts of α- plus 7β-hydroxycholesterol, β-epoxide, 7-ketocholesterol, and total COPs in aerobically packaged cooked pork. The amounts of COPs and lipid oxidation products (TBARS) closely related to the proportion of polyunsaturated fatty acids in meat. The results indicated that the composition of fats in meat is important on the oxidation rates of lipids and cholesterol, and packaging is far more important than irradiation in the formation of COPs and lipid oxidation in cooked meat.

Effects of diet and time on feed on phospholipid fatty acid composition and beef meat flavour

The polyunsaturated fatty acids (PUFA) of the intramuscular phospholipids are the most significant lipids in the development of cooked beef flavour (Mottram and Edwards, 1983). In lamb, differences in n-6 and n-3 fatty acid composition have been shown to be a major factor influencing consumer perception and acceptability (Sañudo et al, 2000). Altering meat PUFA, especially n-3 fatty acids, to improve its value in human nutrition (COMA, 1994) may have effects on flavour and acceptability. The aim of this work was to evaluate differences in flavour perception when intramuscular fatty acid composition is changed in beef meat.

The analysis of polyunsaturated fatty acids in meat by capillary gas‐liquid chromatography

AbstractPolyunsaturated fatty acids (PUFA) of lean meat from domesticated and wild ruminants (cattle, sheep, goat, sambar deer and buffalo) and non‐ruminants (pig, horse and kangaroo) have been examined by capillary gas‐liquid chromatography. Ten different PUFA were found in all specimens with linoleic acid accounting for at least 50% of the total, and arachidonic and linolenic acids being the next most abundant. The total PUFA content for the ruminants ranged from 9 % in beef to 31 % in sambar deer and for the non‐ruminants from 25 % in pig to 43 % in horse. In all species the meat phospholipids (PL) were rich in PUFA (range 24–46% of PL fatty acids), whereas the triglycerides were relatively more saturated (PUFA content range 2–17%). Overall, horse and kangaroo meat had the combination of lowest fat and highest PUFA content, whilst beef and sheep had the highest fat and lowest PUFA content. These results indicate that significant reductions in total fat intake and increases in the proportion of polyunsaturated fat in the diet could be achieved without necessarily requiring a diet low in meat.