Utilization of extruded linseed to modify fatty composition of intensively-reared lamb meat: Effect of associated cereals (wheat vs. corn) and linoleic acid content of the diet

Sixty male lambs were used in two trials to study the efficiency of transfer and elongation of linolenic acid (ALA) in muscle and caudal adipose tissue and to assess factors affecting this process and related changes in fatty acid (FA) profile. In experiment 1, lambs were fed a control diet or extruded linseed (L) diet either with wheat (W, rapid starch) or corn (C, slow starch). In experiment 2, lambs were fed L with “normal” rapeseed, or high-oleic rapeseed, or soybean. In experiment 1, L increased ALA proportion and total n-3 PUFA in muscle and adipose tissue. In adipose tissue but not in muscle, LC lambs had higher proportion of ALA than LW lambs. In experiment 2, increasing linoleic acid (LA) intake increased LA proportion in muscle and adipose tissue but did not modify ALA proportion. Moreover, in muscle, it did not change the desaturation and elongation processes of ALA to long-chain n-3 PUFA.     

Effects of different sources of fat (calcium soap of palm oil vs. extruded linseed) in lactating ewes' diet on the fatty acid profile of their suckling lambs

The main objective of this study was to evaluate the effects of supplementing lactating ewe diets with extruded linseed on the fatty acid (FA) composition of intramuscular and subcutaneous fat depots of suckling lambs. Twenty-four pregnant Churra ewes were divided into two groups based on the milk production, age, body weight and parity, and assigned to one of two treatments. Each ewe of the Control treatment was supplemented with 70 g/day of FAs from a calcium soap of palm oil, while the other treatment group (Lin) was supplemented with 128 g/day of extruded linseed. All lambs were reared exclusively on milk and were slaughtered when they reached 11 kg live weight. FA profiles of ewe milk, lamb meat and subcutaneous adipose tissue were determined by GC. Lamb performance was not affected by the treatments. Muscle fat and adipose tissue from the Lin treatment showed higher proportions of polyunsaturated fatty acids (PUFA). The percentages of α-linolenic (C18:3 n − 3), docosahexaenoic (C22:6 n − 3), vaccenic (trans-11 C18:1) and rumenic (cis-9, trans-11 C18:2) acids in both fat depots were higher in Lin than in Control suckling lambs. Furthermore, meat fat from Lin carcasses displayed a lower n − 6/n − 3 ratio than Control samples. Intramuscular depots clearly showed a greater content of PUFA, including cis-9, trans-11 C18:2, and a lower n − 6/n − 3 ratio than subcutaneous fat. The results from this study demonstrate that dietary extruded linseed supplementation of lactating ewes enhances the nutritional quality of suckling lamb fat depots such as intramuscular and subcutaneous fats.     

Effect of dietary linseed on the nutritional value and quality of pork and pork products: Systematic review and meta-analysis

Nutritional quality of pork is a significant factor for consumers' health. Feeding n-3 PUFA to pigs, using linseed, improves pork nutritional quality. A meta-analysis involving 1006 pigs reported in 24 publications was carried out to assess the effects of dietary linseed on alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) content in muscle and adipose tissue. Data showed positive effects of n-3 PUFA on muscle fatty acid composition: ALA + 137%, EPA + 188%, DPA + 51% and DHA + 12%. Same results were observed in adipose tissue: ALA + 297%, EPA + 149%, DPA + 88% and DHA + 18%. A positive correlation between dietary treatment and ALA and EPA content in muscle (P < 0.001) and adipose tissue (P = 0.036) was observed. A significant association between DPA (P = 0.04) and DHA (P = 0.011) and live weight in muscle was observed. Feeding linseed to pig improves the nutritional pork quality, raising the n-3 PUFA content in muscle and adipose tissue.     

Growth performance and fatty acid profiles of intramuscular and subcutaneous fat from Limousin and Charolais heifers fed extruded linseed

Forty-eight heifers, Limousin (LI) and Charolais (CH) breed, were used to evaluate the effect of a basal mixed diet with linseed supplementation (108g/kg DM) on performance and fatty acid (FA) composition of M. longissimus thoracis (MLT) and subcutaneous fat. The feed intake and weight gains were higher, and feed per gain ratio lower in CH heifers than in LI heifers. The muscle lipids and subcutaneous fat of LI heifers contained significantly more MUFA, PUFA, CLA, and less SFA than the lipids of CH heifers. The feeding of extruded linseed significantly increased the concentration of linolenic acid (C18:3n-3), CLA, and decreased PUFA n-6 to PUFA n-3 ratio in lipids extracted from both tissues. Linseed supplementation decreased SFA and increased PUFA in subcutaneous fat. In MLT lipids of linseed-fed heifers PUFA of the n-3 series were increased. It can be concluded that the growth performance of LI heifers was lower, but that their lipids contained more FA that are thought to be important for human health. The feeding of linseed at 108g/kg DM enhanced the nutritive value of beef in terms of FA profile. Breed differences were generally more important than effects of the diet. Dietary effects, however, were more pronounced in PUFA n-3 and arachidonic acid (C20:4n-6).     

Effect of level of linseed on fatty acid composition of muscles and adipose tissues of lambs with emphasis on trans fatty acids

The effects of linseed content in concentrates on the fatty acid (FA) composition of adipose tissues and muscles of lambs were studied in a 2 × 4 design: males (M) vs. females (F) and linseed content (0%, L0, 3%, L3, 6%, L6, 9%, L9). FA proportions were determined both on a DB-wax and on a CP-Sil column in perirenal (PR), dorsal subcutaneous (SC) adipose tissue and in longissusmus dorsi muscle (IM). No effects of linseed contents in the diet on growth performances either in male or female lambs were observed. Linseed supplementation tended to decrease the fatness score. The proportion of linolenic acid increased linearly with the linseed content in the diet, from: 0.6, 0.5, and 0.5% for L0 to 1.9, 1.6, and 1.3% for L9, in PR, SC and IM, respectively. The increase in n − 3 PUFA and in total PUFA was similar to that of linolenic acid. The n − 6:n − 3 ratio decreased from 5.7, 5.3 and 5.8 for L0 to 1.8, 1.7 and 2.7 for L9, in PR, SC and IM, respectively. There was no change in the proportion of docosahexaenoic acid with linseed supplementation. The proportions of C18:1trans-10 and C18:1trans-11 did not vary in PR, SC and IM with linseed supplementation. The total proportion of trans-octadecenoic acid was high in each tissue type and group of lambs. C18:1trans-10 represented about half of the total trans-octadecenoic isomers. With an increase in linolenic acid, most cis- and trans-octadecenoic isomers also increased, but trans-10 and trans-11 isomers did not and cis-9 and cis-11 isomers decreased. With linseed supplementation there was a decrease in the Δ9 desaturase indices in SC.     

Effect of vitamin E supplementation on fatty acid composition of muscle and adipose tissues of indoor lambs with special attention on rumen-derived trans monounsaturated fatty acids

Thirty male lambs were assigned to one of 3 concentrate diets supplemented with 45 (E0), 286 (E1) or 551 (E2) mg/kg DM of dl-α-tocopheryl acetate to test the effect of vitamin E supplementation on muscle, caudal and perirenal fatty acid (FA) compositions. Specific attention was paid to C18:1 10t, usually observed in high proportions with high-starch or high-unsaturated FA diets. Vitamin E supplementation increased the α-tocopherol plasma concentrations of lambs. It did not modify lamb growth and slaughter parameters. Vitamin E supplementation did not modify FA composition in most tissues but it increased the C18:2 n − 6/C18:3 n − 3 ratio in muscle and adipose tissues of the E1 group compared to E0 and E2 groups. Vitamin E supplementation enhanced the C18:1 10t proportion in muscle and adipose tissues and it decreased the C18:2 9c,11t proportion in adipose tissues, especially in the E2 group. These changes may not be favourable for the nutritional value of lamb meat.     

Effect of level of linseed on fatty acid composition of muscles and adipose tissues of lambs with emphasis on trans fatty acids

The effects of linseed content in concentrates on the fatty acid (FA) composition of adipose tissues and muscles of lambs were studied in a 2 × 4 design: males (M) vs. females (F) and linseed content (0%, L0, 3%, L3, 6%, L6, 9%, L9). FA proportions were determined both on a DB-wax and on a CP-Sil column in perirenal (PR), dorsal subcutaneous (SC) adipose tissue and in longissusmus dorsi muscle (IM). No effects of linseed contents in the diet on growth performances either in male or female lambs were observed. Linseed supplementation tended to decrease the fatness score. The proportion of linolenic acid increased linearly with the linseed content in the diet, from: 0.6, 0.5, and 0.5% for L0 to 1.9, 1.6, and 1.3% for L9, in PR, SC and IM, respectively. The increase in n − 3 PUFA and in total PUFA was similar to that of linolenic acid. The n − 6:n − 3 ratio decreased from 5.7, 5.3 and 5.8 for L0 to 1.8, 1.7 and 2.7 for L9, in PR, SC and IM, respectively. There was no change in the proportion of docosahexaenoic acid with linseed supplementation. The proportions of C18:1trans-10 and C18:1trans-11 did not vary in PR, SC and IM with linseed supplementation. The total proportion of trans-octadecenoic acid was high in each tissue type and group of lambs. C18:1trans-10 represented about half of the total trans-octadecenoic isomers. With an increase in linolenic acid, most cis- and trans-octadecenoic isomers also increased, but trans-10 and trans-11 isomers did not and cis-9 and cis-11 isomers decreased. With linseed supplementation there was a decrease in the Δ9 desaturase indices in SC.     

Effects of feeding different linseed sources on omasal fatty acid flows and fatty acid profiles of plasma and milk fat in lactating dairy cows

The aim of this experiment was to study the effects of feeding different linseed sources on omasal fatty acid (FA) flows, and plasma and milk FA profiles in dairy cows. Four ruminally cannulated lactating Holstein-Friesian cows were assigned to 4 dietary treatments in a 4×4 Latin square design. Dietary treatments consisted of supplementing crushed linseed (CL), extruded whole linseed (EL), formaldehyde-treated linseed oil (FL) and linseed oil in combination with marine algae rich in docosahexaenoic acid (DL). Each period in the Latin square design lasted 21 d, with the first 16 d for adaptation. Omasal flow was estimated by the omasal sampling technique using Cr-EDTA, Yb-acetate, and acid detergent lignin as digesta flow markers. The average DM intake was 20.6 ± 2.5 kg/d, C18:3n-3 intake was 341 ± 51 g/d, and milk yield was 32.0 ± 4.6 kg/d. Milk fat yield was lower for the DL treatment (0.96 kg/d) compared with the other linseed treatments (CL, 1.36 kg/d; EL, 1.49 kg/d; FL, 1.54 kg/d). Omasal flow of C18:3n-3 was higher and C18:3n-3 biohydrogenation was lower for the EL treatment (33.8 g/d; 90.9%) compared with the CL (21.8 g/d; 94.0%), FL (15.5 g/d; 95.4%), and DL (4.6 g/d; 98.5%) treatments, whereas whole-tract digestibility of crude fat was lower for the EL treatment (64.8%) compared with the CL (71.3%), FL (78.5%), and DL (80.4%) treatments. The proportion of C18:3n-3 (g/100 g of FA) was higher for the FL treatment compared with the other treatments in plasma triacylglycerols (FL, 3.60; CL, 1.22; EL, 1.35; DL, 1.12) and milk fat (FL, 3.19; CL, 0.87; EL, 0.83; DL, 0.46). Omasal flow and proportion of C18:0 in plasma and milk fat were lower, whereas omasal flow and proportions of biohydrogenation intermediates in plasma and milk fat were higher for the DL treatment compared with the other linseed treatments. The results demonstrate that feeding EL did not result in a higher C18:3n-3 proportion in plasma and milk fat despite the higher omasal C18:3n-3 flow. This was related to the decreased total-tract digestibility of crude fat. Feeding FL resulted in a higher C18:3n-3 proportion in plasma and milk fat, although the omasal C18:3n-3 flow was similar or lower than for the CL and EL treatment, respectively. Feeding DL inhibited biohydrogenation of trans-11,cis-15-C18:2 to C18:0, as indicated by the increased omasal flows and proportions of biohydrogenation intermediates in plasma and milk fat.     

Fatty acid composition of adipose depots of suckling lambs raised under different production systems

Forty-nine male Talaverana-breed suckling lambs slaughtered at 14 kg live weight were used to study the fatty acid composition of adipose depots of lambs raised under different management systems (pasture or drylot) and diets (maternal milk with or without a concentrate supplement). Drylot lambs displayed a higher fatness score, in addition to greater dorsal fat thickness; these parameters corresponded with a greater percentage of total fat at dissection. Addition of concentrate to the diet did not modify carcass fatness. Drylot lambs presented higher proportions of oleic acid (C18:1) and monounsaturated fatty acids (MUFA) and lower linolenic acid (C18:3) values in subcutaneous and intramuscular fat (muscle longissimus thoracis). The subcutaneous fat of these lambs thus displayed a higher n-6/n-3 PUFA ratio (C18:2/C18:3) than that of pasture-raised ones. Concentrate in the diet of both pasture and drylot lambs resulted in higher linoleic fatty acid (C18:2) and PUFA values and a greater PUFA/SFA ratio in intramuscular fat than the corresponding values of lambs which consumed maternal milk alone. Loin displayed a higher percentage of subcutaneous and intramuscular chemical fat than leg. Compared with intramuscular leg fat (muscle quadriceps femoris), intramuscular loin fat (muscle longissimus thoracis) had lower oleic acid (C18:1) and MUFA values, higher PUFA values and a higher PUFA/SFA ratio, due to greater linolenic acid (C18:3) levels.     

Short communication: the effects of supplementation of various n-3 fatty acids to late-pregnant dairy cows on plasma fatty acid composition of the newborn calves

The passage of long-chain fatty acids (FA) through the placenta in ruminants is limited. However, essential long-chain polyunsaturated FA, and especially n-3 FA, are crucial for normal development of the bovine fetus; therefore, uptake of these FA by the embryo must occur during pregnancy. The objectives of the present study were to examine the effects of enrichment of dam plasma with various n-3 FA during late gestation on newborn calf plasma FA composition. Twenty-seven multiparous cows at 256 d of pregnancy were divided into 3 groups and fed encapsulated fats as follows: 1) control: supplemented at 240 g/d per cow with saturated FA; 2) flaxseed oil (FLX): supplemented at 300 g/d per cow with fat that provided 56.1g/d per cow of α-linolenic acid (ALA) from flaxseed oil; and 3) fish oil (FO): supplemented at 300 g/d per cow with fat that provided 5.8 and 4.3g/d per cow eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil, respectively. Blood samples were taken from dams twice weekly and from calves immediately after calving before first colostrum. The FA composition in plasma was determined in dams at the last sample before parturition, on average 2d before calving. Feeding cows with FLX resulted in a 2.6-fold increase in the proportion of ALA in dam plasma as compared with the control. The proportion of EPA in cow plasma was not different between groups; however, the percentage of docosapentaenoic acid (DPA) was 1.4 and 2 times higher, respectively, in cows fed FLX and FO than in the controls. In addition, the plasma proportion of DHA was 15 times higher in FO cows than in controls. In calves, no differences between groups were observed in the plasma proportions of ALA and EPA; however, the proportion of DHA was 1.9 times higher in the FO calves than in controls. Across treatments, data showed no correlation between the proportions of ALA, EPA, and DPA in dam and calf plasma; however, positive correlation was demonstrated between dams and calves in DHA proportion (r=0.55). In conclusion, the distinct plasma FA profile in newborn calves compared with dams was apparently due to low permeability of the bovine placenta to polyunsaturated FA. Enriching late-gestation dairy cows with n-3 FA increased the proportion of DHA, but not ALA, in newborn calf plasma, probably because of the essentiality of DHA to fetal development.     

Effect of dietary replacement of sunflower oil with linseed oil on intramuscular fatty acids of lamb meat

The effect of stepwise replacement of dietary sunflower oil (SO) with linseed oil (LO) on carcass composition, meat colour and fatty acid (FA) composition of intramuscular lipids of lamb meat was investigated. Thirty-six lambs were fed one of four diets consisting of pellets of lucerne with oil (60 g/kg): the diet varied in the composition of oil added and were: 100% SO; 66.6% SO plus 33.3% LO; 33.3% SO plus 66.6% LO and 100% LO. The experimental period was 7 weeks. Live slaughter weight, hot carcass weight and intermuscular fat percentage of chump and shoulder increased linearly with replacement of SO by LO.     

Effect of whole linseed addition on meat production and quality of Italian Simmental and Holstein young bulls

The effect of long term dietary linseed addition on performance, carcass characteristics and meat quality of Italian Simmental (IS) and Italian Holstein (HI) young bulls was investigated. Thirty-two animals were assigned to 4 groups following a factorial design: 2 breeds - IS and IH - × 2 diets - containing whole ground linseed (5-8% of DM) and control. IS had greater in vivo performance and carcass characteristics than IH. IS muscle had lower C14:0, C16:0, SFA, higher C18:2n-6 cis, PUFAn-6, PUFA and PUFA/SFA proportion than IH in phospholipids (PL) fraction. Linseed inclusion did not affect animal's performance and carcass characteristics. In muscle PL, linseed increased C20:0, C22:0, C23:0, C20:5n-3 and decreased C20:4n-6, PUFAn-6/n-3, PUFAn-6 concentration. Linseed decreased C14:0, C16:0 proportion in neutral lipids (NL) and increased total PUFAn-3, C18:3n-3 proportions both in NL and PL fraction. However, these differences were relatively low from a quantitative point of view.     

Effects of feeding rumen-protected linseed fat to postpartum dairy cows on plasma n-3 polyunsaturated fatty acid concentrations and metabolic and reproductive parameters

High-yielding dairy cows experience a negative energy balance and inflammatory status during the transition period. Fat supplementation increases diet energy density, and plasma n-3 polyunsaturated fatty acids (PUFA) have been proposed to improve immune function. This study tested the hypothesis that dietary supplementation with a rumen-protected and n-3 PUFA-enriched fat could ameliorate both the energetic deficit and immune status of postpartum high-yielding dairy cows, improving overall health and reproductive efficiency. At 11 d in milk (DIM), cows were randomly allocated to groups (1) n-3 PUFA (n = 29), supplemented with encapsulated linseed oil supplying additional up to 64 g/d (mean 25 ± 4 g/d) of α-linolenic acid (ALA), or (2) control (n = 31), supplemented with hydrogenated palm oil without ALA content. Fat supplements of the n-3 PUFA and control groups were available through an automated, off-parlor feeding system, and intake depended on the cow's feeding behavior. Plasma ALA concentrations were higher in n-3 PUFA than control cows, following a linear relation with supplement ingestion, resulting in a lower n-6/n-3 ratio in plasma. Metabolic parameters (body condition score and glucose and β-hydroxybutyric acid blood concentrations) were unaffected, but milk yield improved with increased intake of fat supplements. Plasma total adiponectin concentrations were negatively correlated with ingestion of n-3 PUFA-enriched fat supplement, following a linear relation with intake. Conception rate to first AI increased with higher intake of both fats, but a decrease of calving-to-conception interval occurred only in n-3 PUFA cows. Postpartum ovarian activity and endometrial inflammatory status at 45 DIM were unaffected. In conclusion, this study evinced a positive linear relation between rumen-protected linseed fat intake and plasma n-3 PUFA concentrations, which modulated adiponectin expression and improved reproductive parameters.     

Effects of increased supplementation of n-3 fatty acids to transition dairy cows on performance and fatty acid profile in plasma, adipose tissue, and milk fat

The objective of this study was to determine the effects of feeding an increased amount of extruded flaxseed with high proportions of n-3 fatty acids (FA) to transition dairy cows on performance, energy balance, and FA composition in plasma, adipose tissue, and milk fat. Multiparous Israeli-Holstein dry cows (n = 44) at 256 d of pregnancy were assigned to 2 treatments: (1) control cows were fed prepartum a dry-cow diet and postpartum a lactating-cow diet that consisted of 5.8% ether extracts; and (2) extruded flaxseed (EF) cows were supplemented prepartum with 1 kg of extruded flaxseed (7.9% dry matter)/cow per d, and postpartum were fed a diet containing 9.2% of the same supplement. The EF supplement was fed until 100 d in milk. On average, each pre- and postpartum EF cow consumed 160.9 and 376.2 g of C18:3n-3/d, respectively. Postpartum dry matter intake was 3.8% higher in the EF cows. Milk production was 6.4% higher and fat content was 0.4% U lower in the EF group than in the controls, with no differences in fat and protein yields. Energy balance in the EF cows was more positive than in the controls; however, no differences were observed in concentrations of nonesterified fatty acids and glucose in plasma. Compared with controls, EF cows had greater proportions of C18:3n-3 in plasma and adipose tissue. The proportion of n-3 FA in milk fat was 3.7-fold higher in the EF cows, and the n-6:n-3 ratio was decreased from 8.3 in controls to 2.3 in the EF cows. Within-group tests revealed that the C18:3n-3 content in milk fat in the EF cows was negatively correlated with milk fat percentage (r = –0.91) and yield (r = –0.89). However, no decrease in de novo synthesis of less than 16-carbon FA was found in the EF group, whereas C16:0 yields were markedly decreased. It appears that the enrichment of C18:3n-3 in milk fat was limited to approximately 2%, and the potential for increasing this n-3 FA in milk is higher for cows with lower milk fat contents. In conclusion, feeding increased amounts of C18:3n-3 during the transition period enhanced dry matter intake postpartum, increased milk production, decreased milk fat content, and improved energy balance. Increased amounts of EF considerably influenced the FA profile of plasma, adipose tissue, and milk fat. However, the extent of C18:3n-3 enrichment in milk fat was limited and was negatively correlated with milk fat content and yield.     

Effect of a linseed diet on lipid oxidation, fatty acid composition of muscle, perirenal fat, and raw and cooked rabbit meat

Forty Californian×New Zealand rabbits (1kg initial body weight) were fed a control or a linseed isoenergetic diet containing 30g of extruded linseed/kg. Twenty rabbits for each dietary treatment were slaughtered at 11 weeks of age, at 35 days after the start of the experiment. Feeding the linseed diet increased (P<0.005) the content of 18:2n-3 in muscles, perirenal fat, and raw and cooked meat. The long chain n-3 polyunsaturated fatty acid (PUFA) contents were also increased (P<0.01) in the meat. The linseed diet produced a robust decrease in the n-6/n-3 ratio. Cooking did not alter n-3 PUFA more than saturated fatty acids (SFA) or monounsaturated fatty acids (MUFA). However, n-6 PUFA were altered by cooking. The oxidative stability of Longissimus dorsi was not affected by the linseed diet, even after 300min of forced-oxidation. Inclusion of linseed in rabbit diets is a valid method of improving the nutritional value of rabbit meat.     

The effects of diet and breed on the volatile compounds of cooked lamb

The effect of varying the n-3 polyunsaturated fatty acid (PUFA) composition of lamb muscle on the formation of aroma volatiles during cooking has been examined. The meat was obtained from four groups of Suffolk and Soay lambs fed different supplementary fats: a palm-oil based control; bruised whole linseed, which increased muscle levels of α-linolenic acid (C18:3 n-3); fish oil, which increased eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3); and equal quantities of linseed and fish oil (fat basis). Higher quantities of lipid oxidation products were found in the aroma volatiles of lamb muscle from animals fed fish oil, compared to the control. In particular, unsaturated aldehydes, unsaturated hydrocarbons and alkylfurans increased up to fourfold. These compounds derived from the autoxidation of PUFAs during cooking. Although some of these volatiles were increased in meat from animals fed the linseed supplement, the effect was not as great as with the fish oil fed lambs. Levels of volatiles derived from the Maillard reaction, such as pyrazines and sulfur compounds, were up to four times higher in Soays than Suffolks.     

Effects of incremental amounts of extruded linseed on the milk fatty acid composition of dairy cows receiving hay or corn silage

The effect of supplementation of increasing amounts of extruded linseed in diets based on hay (H; experiment 1) or corn silage (CS; experiment 2) was investigated in regard to dairy performance and the milk fatty acid (FA) composition. In each experiment, 4 lactating multiparous Holstein cows were used in a 4 × 4 Latin square design (28-d periods). The cows were fed a diet (50:50 and 40:60 concentrate:forage ratio for experiments 1 and 2, respectively; dry matter basis) without supplementation (H0 or CS0) or supplemented with 5% (H5 or CS5), 10% (H10 or CS10), or 15% (H15 or CS15) of extruded linseed. Regardless of the forage type, diet supplementation with increasing amounts of extruded linseed had no effect on the dry matter intake, milk yield, or protein content or yield. In contrast, the milk fat content decreased progressively from H0 to H10 diets, and then decreased strongly with the H15 diet in response to increasing amounts of extruded linseed. For CS diets, the milk fat content initially decreased from CS0 to CS10, but then increased with the CS15 diet. For the H diets, the milk saturated FA decreased (−24.1 g/100 g of FA) linearly with increasing amounts of extruded linseed, whereas the milk monounsaturated FA (+19.0 g/100 g), polyunsaturated FA (+4.9 g/100 g), and total trans FA (+14.7 g/100 g) increased linearly. For the CS diets, the extent of the changes in the milk FA composition was generally lower than for the H diets. Milk 12:0 to 16:0 decreased in a similar manner in the 2 experiments with increasing amounts of extruded linseed intake, whereas 18:0 and cis-9 18:1 increased. The response of total trans 18:1 was slightly higher for the CS than H diets. The milk trans-10 18:1 content increased more with the CS than the H diets. The milk cis-9,trans-11 conjugated linoleic acid response to increasing amounts of extruded linseed intake was linear and curvilinear for the H diets, whereas it was only linear for the CS diets. The milk 18:3n-3 percentage increased in a similar logarithmic manner in the 2 experiments. It was concluded that the milk FA composition can be altered by extruded linseed supplementation with increasing concentrations of potentially health-beneficial FA (i.e., oleic acid, 18:3n-3, cis-9,trans-11 conjugated linoleic acid, and odd- and branched-chain FA) and decreasing concentrations of saturated FA. Extruded linseed supplementation increased the milk trans FA percentage.     

Short communication: Feeding linseed oil to dairy goats with competent reticular groove reflex greatly increases n-3 fatty acids in milk fat

A crossover experiment was designed to compare the effects of 2 ways of feeding linseed oil on milk fat fatty acid (FA) composition. Ten lactating goats, trained to keep competent their inborn reticular groove reflex, received a daily dose of linseed oil (38 g/d) either with their solid (concentrate) feed (CON) or emulsified in skim milk and bottle-fed (BOT). Two groups of 5 goats received alternative and successively each of the treatments in two 15-d periods. α-Linolenic acid in milk fat rose up to 13.7% in the BOT versus 1.34% in the CON treatment. The n-6 to n-3 FA ratio was significantly reduced in goats receiving bottle-fed linseed oil (1.49 vs. 0.49). Contents of rumen biohydrogenation intermediates of dietary unsaturated FA were high in milk fat of goats under the CON treatment but low in those in the BOT treatment. These results point to a clear rumen bypass of the bottle-fed linseed oil. This strategy allows obtaining milk fat naturally very rich in n-3 FA and very low in trans FA. Translating this approach into practical farm conditions could enable farmers to produce milk enriched in specific FA.     

Effects of extruded linseed supplementation on n-3 fatty acids and conjugated linoleic acid in milk and cheese from ewes

The objective of this study was to assess the effects of dietary supplementation of extruded linseed on animal performance and fatty acid (FA) profile of ewe milk for the production of n-3 FA- and conjugated linoleic acid-enriched cheeses. A Manchega ewe flock (300 animals) receiving a 60:40 forage:concentrate diet was divided into 3 groups supplemented with 0, 6, and 12 g of extruded linseed/100 g of dry matter for the control, low, and high extruded linseed diets, respectively. Bulk and individual milk samples from 5 dairy ewes per group were monitored at 7, 14, 28, 45, and 60 d following supplementation. Manchego cheeses were made with bulk milk from the 3 treatment groups. Milk yield increased in dairy ewes receiving extruded linseed. Milk protein, fat, and total solids contents were not affected by linseed supplementation. Milk contents of α-linolenic acid increased from 0.36 with the control diet to 1.91% total FA with the high extruded linseed diet. Similarly, cis-9 trans-11 C18:2 rose from 0.73 to 2.33% and its precursor in the mammary gland, trans-11 C18:1, increased from 1.55 to 5.76% of total FA. This pattern occurred with no significant modification of the levels of trans-10 C18:1 and trans-10 cis-12 C18:2 FA. Furthermore, the high extruded linseed diet reduced C12:0 (−30%), C14:0 (−15%) and C16:0 (−28%), thus significantly diminishing the atherogenicity index of milk. The response to linseed supplementation was persistently maintained during the entire study. Acceptability attributes of n-3-enriched versus control cheeses ripened for 3 mo were not affected. Therefore, extruded linseed supplementation seems a plausible strategy to improve animal performance and nutritional quality of dairy lipids in milk and cheese from ewes.     

Effect of a supplementation of Euphorbia heterophylla on nutritional meat quality of Guinea pig (Cavia porcellus L.)

The aim of the present work was to study the effect of dietary supplementation of Euphorbia heterophylla on the quality of the Guinea pig meat. Forty guinea pigs were divided into two groups fed ad libitum during 46 days a Panicum maximum diet (Panicum diet) or a mixed diet (75% Panicum maximum + 25% Euphorbia heterophylla) (Paneuphorbia diet) to compare their effects on performances and on the composition of guinea pig tissues and carcass. Daily weight gain, liver weight, carcass yield, and the lipid content of both the carcass and the perirenal fat were significantly increased by the Paneuphorbia diet. Feeding Paneuphorbia diet increased (P < 0.05) the n-3 PUFA content in perirenal fat, muscle, liver and in the carcass and decreased (P < 0.05) the n-6/n-3 ratios in all these tissues and the carcass. In conclusion, this study shows that Euphorbia heterophylla is a source of n-3 fatty acids which can improve significantly the n-3 PUFA content of Guinea pig meat and carcass.