Tuna Oil Supplementation Research Articles

Omega-3 meat enrichment and L-FABP, PPARA, and LPL genes expression are modified by the level and period of tuna oil supplementation in slow-growing chickens.

This study proposes a strategy to manipulate the fatty acid (FA) content in slow-growing Korat chicken (KRC) meat using tuna oil (TO). To determine the optimal level and feeding period of TO supplementation, we conducted a study investigating the effects of dietary TO levels and feeding periods on meat quality, omega-3 polyunsaturated fatty acid (n-3 PUFA) composition, and gene expression related to FA metabolism in KRC breast meat. At 3 wk of age, 700 mixed-sex KRC were assigned to seven augmented factorial treatments with a completely randomized design, each consisting of four replicate pens containing 25 chickens per pen. The control group received a corn-soybean-based diet with 4.5% rice bran oil (RBO), while varying amounts of TO (1.5%, 3.0%, or 4.5%) replaced a portion of the RBO content in the experimental diets. The chickens were fed these diets for 3 and 6 wk, respectively, before being slaughtered at 9 wk. Our results indicated no significant interactions between TO levels and feeding periods on the growth performance or meat quality of KRC (P > 0.05). However, the liver fatty acid-binding protein gene (L-FABP, also known as FABP1), responsible for FA transport and accumulation, showed significantly higher expression in the chickens supplemented with 4.5% TO (P < 0.05). The chickens supplemented with 4.5% TO for a longer period (3 to 9 wk of age) exhibited the lowest levels of n-6 PUFA and n-6 to n-3 ratio, along with the highest levels of eicosapentaenoic acid, docosahexaenoic acid, and n-3 PUFA in the breast meat (P < 0.05). However, even a short period of supplementation with 4.5% TO (6 to 9 wk of age) was adequate to enrich slow-growing chicken meat with high levels of n-3 PUFA, as recommended previously. Our findings indicated that even a short period of tuna oil supplementation could lead to desirable levels of omega-3 enrichment in slow-growing chicken meat. This finding has practical implications for the poultry industry, providing insights into optimal supplementation strategies for achieving desired FA profiles without adversely affecting growth performance or meat quality.

Novel high-docosahexaenoic-acid tuna oil supplementation modulates gut microbiota and alleviates obesity in high-fat diet mice.

Studies have documented the benefits of fish oil in different diseases because of its high n‐3 polyunsaturated fatty acid content. However, these studies mostly used commercially available fish oil supplements with a ratio of 18/12 for eicosapentaenoic acid and docosahexaenoic acid (DHA). However, increasing DHA content for this commonly used ratio might bring out a varied metabolic effect, which have remained unclear. Thus, in this study, a novel tuna oil (TO) was applied to investigate the effect of high‐DHA content on the alteration of the gut microbiota and obesity in high‐fat diet mice. The results suggest that high‐DHA TO (HDTO) supplementation notably ameliorates obesity and related lipid parameters and restores the expression of lipid metabolism‐related genes. The benefits of TOs were derived from their modification of the gut microbiota composition and structure in mice. A high‐fat diet triggered an increased Firmicutes/Bacteroidetes ratio that was remarkably restored by TOs. The number of obesity‐promoting bacteria—Desulfovibrio, Paraeggerthella, Terrisporobacter, Millionella, Lachnoclostridium, Anaerobacterium, and Ruminiclostridium—was dramatically reduced. Desulfovibrio desulfuricans, Alistipes putredinis, and Millionella massiliensis, three dysbiosis‐related species, were especially regulated by HDTO. Regarding the prevention of obesity, HDTO outperforms the normal TO. Intriguingly, HDTO feeding to HFD‐fed mice might alter the arginine and proline metabolism of intestinal microbiota.

Effect of Low Dose Docosahexaenoic Acid-Rich Fish Oil on Plasma Lipids and Lipoproteins in Pre-Menopausal Women: A Dose⁻Response Randomized Placebo-Controlled Trial.

Omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation has been shown to improve plasma lipid profiles in men and post-menopausal women, however, data for pre-menopausal women are lacking. The benefits of intakes less than 1 g/day have not been well studied, and dose–response data is limited. The aim of this study was to determine the effect of low doses of docosahexaenoic acid (DHA)-rich tuna oil on plasma triglyceride (TG) lowering in pre-menopausal women, and investigate if low dose DHA-rich tuna oil supplementation would increase the low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particle sizes. A randomized, double-blind, placebo-controlled trial was conducted, in which 53 healthy pre-menopausal women with mildly elevated plasma TG levels consumed 0, 0.35, 0.7, or 1 g/day n-3 LCPUFA as HiDHA™ tuna oil or placebo (Sunola oil) capsules for 8 weeks. Supplementation with 1 g/day n-3 LCPUFA, but not lower doses, reduced plasma TG by 23% in pre-menopausal women. This was reflected in a dose-dependent reduction in very-low-density lipoprotein (VLDL)-TG (R2 = 0.20, p = 0.003). A weak dose-dependent shift in HDL (but not LDL) particle size was identified (R2 = 0.05, p = 0.04). The results of this study indicate that DHA-rich n-3 LCPUFA supplementation at a dose of 1 g/day is an effective TG-lowering agent and increases HDL particle size in pre-menopausal women.

Linseed oil or tuna oil supplementation in slow-growing chicken diets: Can their meat reach the threshold of a “high in n-3 polyunsaturated fatty acids” product?

SUMMARY A strategy for enriching the meat of slow-growing chickens with n-3 fatty acids from tuna oil (TO) or linseed oil (LO) is proposed. The effects of TO or LO supplementation on the growth performance of the chickens and the quality, cholesterol content, and fatty acid composition of the meat were examined. A total of 560 21-day-old mixed-sex Thai indigenous crossbred chickens was assigned to a completely randomized design with 7 treatment diets and 4 replicates. The control group consumed a basal diet of corn-soybean meal supplemented with rice bran oil (RBO; 6%). In the experimental diets, RBO was replaced with 2, 4, or 6% TO (TO2, TO4, and TO6) or with 2, 4, or 6% LO (LO2, LO4, and LO6). All groups received 6% added oil. The TO6 diet lowered the final BW and FCR. The boiling loss of breast meat was highest in LO6 and differed from the losses in the control and TO2 groups. Meat from TO4 and LO6 yielded the lowest n-6/n-3 ratio. The alpha-linolenic acid (ALA) content linearly increased across the LO group. The n-3 fatty acid accumulation in the slow-growing chickens was nutritionally valuable for human consumption. Breast meat from TO2 and TO4 provided >250 mg docosahexaenoic acid (DHA) per 100 g fresh meat. Thigh meat from at least 2% TO or 6% LO contained >80 mg (eicosapentaenoic acid + DHA)/100 g meat and 600 mg ALA/100 g meat, respectively, reaching the “high in n-3 polyunsaturated fatty acids” threshold in dietary recommendations.

Sex-Based Differences in Gut Microbiota Composition in Response to Tuna Oil and Algae Oil Supplementation in a D-galactose-Induced Aging Mouse Model.

Our previous work indicated that a mixture of tuna oil and algae oil treatment in male mice effectively relieved D-galactose (D-gal)-induced aging and resulted in gut microbiota alterations, and that the best anti-aging effects were observed for a tuna oil to algae oil ratio of 1:2. However, the possibility of a sex-based difference in the anti-aging effect of the tuna oil and algae oil mixture or gut microbiota variation, has rarely been investigated. In this study, the anti-aging effect of an oil mixture (1:2) in male and female mice was measured, and oil treatment improved the learning and cognition of mice that were damaged by D-gal, increased the activities of anti-oxidative enzymes, and decreased the level of MDA, which acted as a hallmark of oxidative damage to lipids. Male mice showed better anti-aging effects than female mice with a specific oil mixture ratio, and the clinical drug donepezil showed a similar or better effect on aging alleviation than oil treatments in both sexes. On the other hand, the same oil treatment led to different gut microbiota composition alterations in male and female mice. Redundancy analysis (RDA) identified 31 and 30 key operational taxonomic units (OTUs) in the male and female mice, respectively, and only three of these OTUs overlapped. Moreover, the abundance of Lactobacillus and several probiotic-like butyric acid producers was higher in male mice than in female mice, whereas the abundance of some inflammation-related genera, such as Clostridium XlVa, was lower in male mice. In conclusion, this study indicated the sex-based differences related to the anti-aging effects of tuna oil and algae oil treatment are accompanied by sex-based differences in gut microbiota modulation.

Improvement of Major Depression is Associated with Increased Erythrocyte DHA

The aim of this study was to determine if changes in omega-3 polyunsaturated fatty acid status following tuna oil supplementation correlated with changes in scores of depression. A total of 95 volunteers receiving treatment for major depression were randomised to consume 8×1g capsules per day of HiDHA (2g DHA, 0.6g EPA and 10mg Vitamin E) or olive oil (placebo) for 16weeks, whilst undergoing weekly counseling sessions by trained clinical psychologists using a standard empirically validated psychotherapy. Depression status was assessed using the 17 item Hamilton rating scale for depression and the Beck Depression Inventory by a psychodiagnostician who was blind to the treatment. Blood was taken at baseline and 16weeks (n=48) for measurement of erythrocyte fatty acids. With HiDHA supplementation, erythrocyte DHA content rose from 4.1±0.2 to 7.9±0.4% (mean±SEM, p<0.001) of total fatty acids but did not change (4.0±0.2 to 4.1±0.2%) in the olive oil group. The mean changes in scores of depression did not differ significantly between the two groups (-12.2±2.1 for tuna oil and -14.4±2.3 for olive oil). However, analysis of covariance showed that in the fish oil group there was a significant correlation (r=-0.51) between the change in erythrocyte DHA and the change in scores of depression (p<0.05). Further study of the relationship between DHA and depression is warranted.

Enrichment withn-3 fatty acid by tuna oil feeding of pigs: changes in composition and properties of bacon and different sausages as affected by the supplementation period

Khiaosa-ard R., Chungsiriwat P., Chommanart N., Kreuzer M. and Jaturasitha S. 2011. Enrichment with n-3 fatty acid by tuna oil feeding of pigs: changes in composition and properties of bacon and different sausages as affected by the supplementation period. Can. J. Anim. Sci. 91: 87–95. Belly, lean from the shoulder and backfat obtained from 80 pigs, fed either no or 1.6 kg tuna oil during fattening (35–90 kg body weight), were used to prepare bacon, Chinese-style sausage and Vienna-style sausage. The tuna oil had been supplemented either initially, at the end, or continuously during fattening. In all meat products, tuna oil supplementation clearly increased contents of n-3 fatty acids (FA), especially of the long-chain n-3 FA. Differences among supplementation periods were pronounced only in the n-3 FA proportion of total FA being lower with early tuna oil feeding. Thiobarbituric acid value, which was high in dry Chinese-style sausage, was mostly enhanced by tuna oil, whereas the period of tuna oil supplementation had no systematic influence. In conclusion, any mode of tuna oil supplementation investigated was efficient in enriching n-3 FA, but care should be taken in producing dry sausages due to their susceptibility to rancidity during storage time.

Human milk fatty acids from lactating mothers of preterm infants: A study revealing wide intra- and inter-individual variation

Docosahexaenoic acid (DHA) and arachidonic acid (AA) are important nutrients in the preterm diet and fixed ratios have been proposed for formula. We evaluated the intra- and inter-individual variation in milk fatty acids from mothers of preterm infants involved in a randomised trial of tuna oil or placebo supplementation. Milk samples were collected every 2 weeks while infants were hospitalised and fatty acids analysed by capillary gas chromatography. DHA was higher in milk of supplemented mothers than control (% total fatty acids, mean±SD, treatment 0.9±0.4, control 0.3±0.1, p<0.0005) and ranged between 0.3–2.5% and 0.1–1.1%, respectively. AA did not differ between groups and ranged between 0.2–0.9% and 0.3–0.9%, respectively. Control mothers milk had wider AA:DHA ratio than treatment mothers (0.4–3.2 versus 0.2–2.1). Due to the wide variation in milk AA and DHA, statements recommending infant formula based on a fixed AA:DHA ratio should be re-examined.

Backfat Characteristics of Barrows and Gilts Fed on Tuna Oil Supplemented Diets during the Growing-finishing Periods

This study was conducted to evaluate the effect of supplementing tuna oil to diets of growing-finishing pigs (barrows and gilts) on backfat characteristics when slaughtered at different weights. Four hundred and eighty crossbred (Large White×Landrace× Duroc) pigs averaging 30 kg were allotted to 12 treatment combinations (40 pigs/treatment combination) in a completely randomized design with a 2×2×3 factorial arrangement of treatments. The treatments were: dietary tuna oil supplementation (0 and 2%); sex (barrows and gilts); and slaughter weight (90, 100 and 110 kg). As pigs reached their slaughter weight, they were randomly selected (8 pigs/treatment combination; 96 pigs in total) and slaughtered. Backfat colour, hardness and fatty acid profile were assessed. There was significant (p<0.05) differences in colour (L* and a* values) among treatments. Backfat of control group was harder than those on the tuna oil (p<0.001) and also that of barrows was harder than of gilts (p<0.05). In addition, the thiobarbituric acid reactive substances (TBARS) values of fat from tuna oil group stored for 3 days was higher (p<0.001) than that of the control group. The TBARS values of gilts tended to be higher than that of barrows and it increased with increasing slaughter weight in the tuna oil group. The cholesterol and triglyceride levels were not affected by diet and sex but the triglyceride level increased with increasing slaughter weight (p<0.01). The tuna oil group had higher polyunsaturated fatty acid (PUFA) content, ratio of PUFA: saturated fatty acid (SFA) and total n-3 fatty acids but lower monounsaturated fatty acids content and n-6:n-3 fatty acids than those of the control group (p<0.01). Gilts had higher PUFA and n-6 fatty acids in backfat than barrows (p<0.05). The backfat from both 90 and 100 kg slaughter weight groups had a lower ratio of n6:n3 fatty acid than that of the 110 kg slaughter weight group (p<0.05). However this was more pronounced in tuna oil group. The PUFA: SFA was also increased while the n-6:n-3 ratio tended to reach the recommended levels for healthy eating in human beings of <5. However, due to oxidative susceptibility, barrows should not be slaughtered at more than 100 kg for the meat to be acceptable to

Efficiency of Tuna Oil to Modify Meat Quality and Fatty Acid Profile in Pork as Affected by Gender and Slaughter Weight

Jaturasitha, S., Srikanchai, T. and Kreuzer, M. 2007. Efficiency of tuna oil to modify meat quality and fatty acid profile in pork as affected by gender and slaughter weight. J. Appl. Anim. Res., 32: 125–131. In order to determine the highest efficiency of tuna oil (TO) supplementation, 48 barrows and 48 gilts fed on diets containing 0 or 20 g TO/kg diet were fattened either to 90, 100 or 110 kg live weight (2x2x3-factorial design). Variables describing water-holding capacity and texture of the M. longissimus dorsi were generally not influenced by TO as such. With one exception in shear force, no significant interactions among experimental factors were found. Incorporation of highly unsaturated n-3 fatty acids increased with TO supplementation, but this at the cost of fat shelf life. The n-3 fatty acids were reduced in proportion with increasing slaughter weight. In contrast, gender differences in polyunsaturated fatty acids found in unsupplemented pigs (higher in gilts), were balanced by TO supplementation. In conclusion, TO-fed pigs should be slaughtered early, while there is no need to differentiate for gender.

Supplementation of grazing dairy cows with rumen-protected tuna oil enriches milk fat with n-3 fatty acids without affecting milk production or sensory characteristics.

The present study was conducted to determine the pattern of incorporation of dietary EPA and docosahexaenoic acid (DHA) into milk, and to evaluate consequent changes in milk fat composition and sensory characteristics. Fourteen multiparous cows in early lactation were divided into two groups and were offered supplements for 10 d. While individual stalls after each morning milking, one group was offered a mixture of rumen-protected tuna oil (RPTO)-soyabean supplement (2 kg; 30:70, w/w; +RPTO) and the second group was offered the basal ration without RPTO (-RPTO). Both groups grazed together on a spring pasture after supplementation. Feeding supplemental RPTO increased the concentrations of EPA and DHA in milk fat from undetectable levels in -RPTO cows to 6.9 and 10.1 g/kg milk fat respectively. Total n-3 PUFA concentration in milk fat was increased three- to fourfold by tuna-oil supplementation (8.4 to 32.0 g/kg milk fat). There were no significant effects on milk production (35.4 v. 33.9 l/d), milk protein (28.2 v. 30.1 g/kg) or milk fat (36.2 v. 40.4 g/kg for -RPTO and +RPTO respectively). The concentration of total saturated fatty acids in milk fat was significantly reduced (568 v. 520 g/kg total fatty acids) and there was a 17 % reduction in the atherosclerotic index of milk after tuna-oil supplementation. Untrained consumer panellists (n 61) rated milk from both groups of cows similarly for taste and smell. We conclude that it is possible to enrich milk with n-3 PUFA without deleterious effects on yield, milk composition or sensory characteristics.

Fish oil metabolism in ruminants: III. Transfer of n−3 polyunsaturated fatty acids (PUFA) from tuna oil into sheep’s milk

A study was conducted to determine whether protected tuna oil can be used to enrich sheep’s milk with eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6) without affecting milk yield or composition. Sixteen sheep in late lactation were selected from a dairy herd and assigned into two groups: Control (C) and protected tuna oil (PTO)-supplemented group. The two groups were run in adjacent paddocks where both had ad libitum access to oaten hay. Both were group-fed lupins (500 g per animal per day) in a trough after morning (06:00 h) and afternoon (15:00 h) milking. At morning milking the PTO group were offered a mixture of chaff (160 g) and molasses-coated (80:20, w/w), protected tuna oil supplement (150 g). At each milking, the control group were offered 50–100 g of a mixture of oaten chaff (0.70) and lupins (0.30) for contentment during milking. Supplement feeding lasted 10 days and milk samples were collected from Day 0 (pre-feeding) to 6 days post-feeding period. Tuna oil supplementation did not affect daily milk yield (722±81 ml versus 716±80 ml), fat (74±8.3 g/kg versus 77±0.8.6 g/kg) or protein percent (54±6.0 g/kg versus 56±6.3 g/kg; C versus PTO, respectively). No apparent residual effect on milk yield or composition was detected 6 days post-feeding period. The levels of EPA and DHA in milk fat from the PTO group increased linearly from Day 2 (0.7±0.7 g/kg and 1.7±0.6 g/kg) up to Day 6 (3.2±0.8 g/kg and 170±1.8 g/kg) and tended to plateau thereafter (Day 10 values: 4.7±0.5 g/kg and 19±0.9 g/kg, respectively). Six days after the supplement-feeding period, the milk from the PTO group was still significantly enriched with n−3 PUFA (EPA: 2.3±0.9 g/kg; DHA: 6.5±0.9 g/kg). No EPA or DHA was detected in milk samples from the non-supplemented group. The apparent transfer of dietary EPA and DHA to milk was 0.21±0.02 for EPA and 0.18±0.03 for DHA (computed using milk samples from Day 10). A cup (250 ml) of such n−3 PUFA-enriched milk will provide two-thirds (437 mg, 0.67) of the recommended daily intake of EPA plus DHA (650 mg) for adults. This study provides an approach that enables enrichment of milk with health-enhancing fatty acids without deleterious consequences on milk yield or composition.

Enrichment of Pork with Omega-3 Fatty Acids by Tuna Oil Supplements: Effects on Performance as well as Sensory, Nutritional and Processing Properties of Pork

The effects of tuna oil supplementation (0, 1, 2 and 3%) to pig diets on growth and carcass yield as well as meat quality were determined in 40 crossbred pigs. Animals were fattened from 30 to 90 kg of live-weight. Twenty-four hours after slaughter, following various early- and late-post mortem measurements, loin, backfat and belly were prepared from the carcasses. Bacon was produced from the belly part by curing and smoking. Neither performance (feed intake, daily gains, feed conversion efficiency) nor carcass quality (slaughter weight, dressing percentage, lean percentage, nutrient composition of the loin) were significantly affected by tuna oil supplementation. Tuna oil also had no clear effects on early- and late-post mortem meat quality traits, water-holding capacity and tenderness of the M. longissiumus dorsi (LD). Colour traits of LD and backfat, and backfat firmness were not significantly affected by tuna oil, either. However, there was a certain trend to elevated fat contents of LD (and bacon), but not of backfat, with increasing levels of tuna oil in feed. Pigs receiving elevated proportions of tuna oil expressed lower VLDL cholesterol and triglyceride concentrations in blood plasma, whereas the cholesterol content of LD, backfat and bacon did not reflect this trend. Effects of tuna oil on fatty acids in LD, backfat and bacon were often small in extent, except those concerning the long-chain polyunsaturated fatty acids. With 3% tuna oil in the diet, the contents of the particularly desired omega-3 fatty acids, C20:5 and C22:6, were 0.1 and 0.2 g/kg in LD. The corresponding values for backfat and bacon were 2.6 and 12.6 g/kg, and 1.3 and 9.2 g/kg, respectively. Tuna oil supplementation was associated with significant adverse effects on flavour and overall acceptance of bacon (not significant in LD although numerically the same trend was noted), but these effects on sensory ratings were limited in extent. Also shelf life of the products, determined as TBA value after different storage periods at 4°C in LD, backfat and bacon, was significantly reduced. Overall, the present study suggests that omega-3 fatty acids may be enriched in pork by feeding tuna oil with few undesired side-effects, particularly those on sensory perception and shelf life, suggesting immediate consumption of the products is advisable. Most economically important traits (performance, slaughter and physical meat quality) remained unaffected. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 11 : 1622-1633)

Utilisation of fish oil in ruminants: I. Fish oil metabolism in sheep

Five sheep with rumen and abomasal cannulae were offered three diets sequentially in the order: control (C) pellets (lucerne hay-oat grain: 60/40, w/w), control plus unprotected tuna oil (UTO pellets), and control plus tuna oil protected (casein-formaldehyde matrix) against ruminal biohydrogenation (PTO pellets). In supplemented diets, tuna oil constituted 3% (w/w) of total dry matter (DM), and each supplement was fed for 12 days, with 9 days allowed between the two fish oil feeding periods to minimise carry-over effects. Daily DM intake was 785±38 g/head during the control period. It was significantly reduced by UTO feeding (6.2%, P<0.05) but not PTO feeding. The level of EPA in the abomasum during PTO feeding was double that measured during UTO feeding (1.30 versus 0.61% of FA, P<0.05). The level of DHA in the abomasum did not significantly differ between UTO and PTO feeding periods. Both tuna oil supplements significantly increased the levels of 18:1 trans and that of a fatty acid derivative identified as 10-hydroxystearic acid (10-HSA) in both the rumen and abomsum. Tuna oil supplementation also altered the fatty acid composition of plasma lipid fractions and 10-HSA was solely incorporated into plasma free fatty acids. This study indicates that substantial protection of tuna oil against ruminal hydrogenation inhibited reduced feed intake, but increased the proportion of 18:1 trans isomer and fatty acids derivatives (10-HSA), which indicate interference with metabolism in the rumen.