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

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

Effect of dietary fat type on meat quality and fatty acid composition of various tissues in growing-finishing swine

Thirty-six castrated male growing pigs were used to study the effect of dietary beef tallow (BT) versus sunflower oil (SO) on meat quality and fatty acid composition of various tissues. The diets used contained either 5% (w/w) of the variable fat source. The fat type had no significant effect on carcass traits (carcass weight, back-fat thickness, fat-lean ratio) and meat quality (colour, pH(1), pH(U), drip losses, cooking losses, shear force, sacromere length, loin moisture, loin marbling). The diet with SO instead of BT significantly increased the incorporation of polyunsaturated fatty acids in adipose tissues, loin and liver at the expense of the sum of saturated and monounsaturated fatty acids. In erythrocytes, the diet containing SO raised the contents of saturated and polyunsaturated fatty acids and lowered that of monounsaturated fatty acids. In particular, the SO diet produced an increase in the content of linoleic acid (C18:2n-6) in the various tissues. It is concluded that feeding a diet with SO instead of BT altered the fatty acid composition of tissues without simultaneously affecting various characteristics of meat quality.     

Performance of dairy cows fed roasted sunflower seed

The objectives of this study were to determine the effects on milk yield, milk composition, ruminal fermentation and total tract nutrient utilization of feeding roasted whole sunflower seed to dairy cows. Three diets were formulated: a control diet with no sunflower seed (NSF), a raw sunflower seed diet (USF) and a roasted sunflower seed diet (RSF). The level of sunflower seed in USF and RSF was 78 g kg^?1 of dry matter (DM). The effects of dietary treatments on yield and composition of milk were determined using nine Holstein cows in three 3 × 3 Latin squares. Three ruminally fistulated cows were used to determine the effects of dietary treatments on ruminal fermentation and total tract nutrient digestibilities. Cows fed sunflower seed diets consumed 8% less (P < 0.05) DM but produced similar amounts of milk as cows fed NSF. However, milk fat content (30.7 vs 33.5 g kg^?1) and yield (1.33 vs 1.47 kg day^?1) were lower (P < 0.05) for cows fed USF and RSF than for those fed NSF. Supplemental sunflower seed had no effect on concentrations and yields of other milk components. The concentrations of short‐chain (C_4:0 to C_12:0) and medium‐chain (C_14:0 to C_16:0) fatty acids were, respectively, 27% and 29% lower (P < 0.05) while those of long‐chain fatty acids (C_18:0 to C_18:3) were 51% higher (P < 0.05) in the milk of cows fed USF and RSF than for cows fed NSF. Ruminal pH, ammonia N and total volatile fatty acids were not affected by dietary treatments. Feeding sunflower seed (USF or RSF) reduced (P < 0.05) the concentration of acetate and increased (P < 0.05) the concentration of propionate. Total tract nutrient digestibilities were not affected by sunflower seed supplementation or by heat treatment. Supplementing dairy cow diets with unheated or roasted sunflower seed improved the efficiency of milk production and increased concentrations of long‐chain and polyunsaturated fatty acids. Feeding sunflower seed at up to 78 g kg^?1 of diet DM had no adverse effects on nutrient utilization. Roasting had no additional benefits on milk yield or milk fatty acid composition. Copyright © 2004 Society of Chemical Industry     

The production of milk rich in protein and low in fat, the fat having a high polyunsaturated fatty acid content

In two experiments, dairy heifers were offered a basal diet of ground dried grass cubes and flaked maize. In Experiment 1, the diet contained equal amounts of these components whereas, in Experiment 2, the proportions were varied from all-grass to equal amounts of grass and flaked maize. Before and after the main part of each experiment, the animals were offered a diet containing hay, molassed sugar beet pulp and barleybased concentrates. Compared to this diet, the grass cubes-flaked maize diet reduced the fat content of the milk and increased the crude protein content. The proportions of all the milk fatty acids up to 18:0 were reduced and those of 18:1, 18:2 and 18:3 were increased. In Experiment 1, the basal diet of grass cubes and flaked maize was supplemented with 180 and 360 g day^?1 soya bean oil given as crushed, unextracted soya beans or with 180 g day^?1 soya bean oil given as a formaldehyde-treated caseinoil preparation but none of these supplements had any effect on the composition of the milk. In Experiment 2, the crude protein content of the milk increased as the proportion of flaked maize in the diet was increased. Otherwise, there were no differences between the different diets.     

Effect of oil sources and vitamin E levels in the diet on the composition of fatty acids in rooster thigh and chest meat

The aim of this study was to evaluate the inclusion of different oil sources and dietary supplementation with vitamin E on the composition of fatty acids in rooster meat. Two hundred and forty 30‐week‐old White Leghorn roosters were distributed in a completely randomized factorial arrangement of 5 × 2, using five oil sources (sunflower, soybean, canola, linseed and fish) and two levels of antioxidant (30 and 400 mg vitamin E kg^?1 of diet). The intake of fish and canola oil in the diet reduced (P < 0.05) the content of saturated and unsaturated fatty acids in the thigh meat. Amongst the unsaturated fatty acids in the thigh, the fish and canola oil reduced (P < 0.05) the level of ω6 fatty acid, with a consequent decrease in the ratio ω6:ω3. The diet with fish oil increased (P < 0.05) the content of C22:6ω3 in the thigh meat. The use of linseed oil resulted in a significant reduction of the ratio of ω6:ω3 fatty acid in the thigh. The use of soybean oil in the diet increased (P < 0.05) the content of saturated and unsaturated fatty acids in the thigh, specifically in the content of ω6. The inclusion of vitamin E increased the polyunsaturated fatty acids in the chest meat, such as C18:3ω3, C20:5ω3 and C22:6ω3. Copyright © 2004 Society of Chemical Industry     

Intramuscular fatty acid composition of lambs fed diets containing alternative protein sources

Thirty male Merinizzata italiana lambs were divided into three groups after weaning according to live weight. The diet of the three groups differed in the main protein source used in the concentrate, soybean meal for treatment SBM, faba bean for treatment FB and peas for treatment PEA. Lambs were fed ad libitum and slaughtered at about 160 days of age. Meat from the PEA group had higher proportions of the essential fatty acids C18:2 ω-6 and C18:3 ω-3 than from FB and SBM lambs and consequently its derivatives, C20:4 ω-6 and C20:5 ω-3 respectively, were higher in meat from PEA animals, compared to SBM and FB ones. The total n-3 fatty acids were highest in meat from PEA lambs and consequently PEA lambs showed a more favourable n-6/n-3 ratio. In conclusion the use of legume seeds such as peas in lamb diets positively affected intramuscular fatty acid composition.     

Genotype,environment and genotype × environment effects on trypsin inhibitor in peas

Four multiparous ruminally canulated cows and four primiparous cows without a ruminal cannula were used in a 4 × 4 Latin square experiment to study the effect of dietary fat source on milk fatty acid composition. Cows were fed a diet containing 550 g lucerne silage and 450 g concentrate kg^?1 dietary DM. The four diets were control and fat supplementation (32 g fat kg^?1 diet DM) as roasted soya beans, calcium salts of palm oil fatty acids (Megalac®). or hydrogenated tallow (Alifet®). Cows fed supplemental fat as roasted soya beans. Megalac®. or Alifet® produced 33.8, 32.6, and 32.5 kg day^?1 of 3.5% FCM. respectively, compared with 31.6 kg day^?1 with no fat supplementation. Addition of fat decreased milk protein percentage. Milk fat percentage was increased with Megalac® and decreased with Alifet® feeding. Dietary fat decreased the proportion of short- and medium-chain fatty acids (C6-C14:0) in milk and increased the proportion of long-chain fatty acids (C16 : 0 and longer). Roasted soya beans were most effective in reducing C16 : 0 and increasing C18 : 1, C18 : 2 and C18 : 3 acids in milk fat. Megalac® did not decrease milk C16 : 0 content, and neither Megalac® nor Alifet® affected C18 : 2 content.     

The use of chromic oxide as a food marker —a warning

Four mixtures of ground barley and soya bean meal were prepared; the first had no further additive, the second had 10% soya bean oil, the third 0.05% chromic oxide and the fourth both 10% soya bean oil and 0.05% chromic oxide. Each of these mixtures was then dried in three ways: at 30°C in vacuo and at 60 and 100°C in a forceddraught oven. The total fatty acid content and the fatty acid composition of each sample was determined either by direct esterification of the fatty acids with methanolsulphuric acid or by extraction into chloroform-methanol followed by esterification with sodium methoxide. When the mixture containing both oil and chromic oxide was heated at 100°C, about 25% of the polyunsaturated fatty acids were lost when they were directly esterified and about 50% when the fat was first extracted from the mixture. It is concluded that this loss is probably due to oxidation of the polyunsaturated fatty acids by the chromic oxide and that the additional loss observed when the extraction method was used is due to partial insolubilisation of the triglyceride by these oxidised fatty acids.     

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

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

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.     

Influence of the oxidative quality of dietary oil on broiler meat storage stability

Broilers were fed a high fat diet containing 11% oil (9% rapeseed oil, 2% soya bean oil) and the oil was given either as fresh (peroxide value of 1 meqv. O₂kg⁻¹ oil) or as highly oxidised (peroxide value of 156 meqv. O₂kg⁻¹ oil). Diets were supplemented with 46 mg all-rac--tocopheryl acetate kg⁻¹ diet, resulting in a tocopherol content of 80.8 mg -tocopherol and 58.6 mg γ-tocopherol per kg diet in the fresh oil diet and of 44.0 mg -tocopherol and 18.3 mg γ-tocopherol per kg diet in the oxidised oil diet, respectively, reflecting the degradation of the natural occurring tocopherols in the oxidised diet. Only minor differences were seen with respect to fatty acid composition in muscles from birds fed the two diets. The oxidation of the dietary oil lowered lipid stability significantly (p < 0.01) in both raw and precooked meats during chill storage, whereas only minor effects on the stability of frozen meat were seen. Tocopherol levels were significantly lower (p < 0.01) in muscles from birds fed the oxidised oil diet, explaining the decreased lipid stability of meat from these birds. Thigh meat was more susceptible to lipid oxidation during storage than breast meat, regardless of dietary treatment, although thigh meat had markedly higher tocopherol levels than breast meat. The molar ratio of PUFA > 18:2 (polyunsaturated fatty acids with three or more double bonds) to -tocopherol was significantly (p < 0.01) higher in thigh meat compared with breast meat, explaining the lower stability of the former during storage.     

兔肉脂肪酸组成的气相色谱法分析

采用极性毛细管柱气相色谱法,测定了兔肉脂肪酸组成的相对百分含量和实际含量.测定结果表明,此方法能准确分离出兔肉中的主要8种脂肪酸:豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、亚麻酸和花生酸,有较好的精密度、重复性、可靠性.     

Changes in lipid components during the development of the french bean seed (Phaseolus vulgaris)

Changes in lipid classes, fatty acid composition and distribution have been monitored during the germination, development and maturation of the French bean seed Phaseolus vulgaris. A lipase activity profile over time was also determined. Ungerminated seeds contained high levels of triglycerides and free fatty acids, but low levels of polar lipids, monoglycerides, and diglycerides. Five days after germination there was a decrease in the quantity of triglycerides and free fatty acids and a concomitant increase in the levels of monoglycerides, diglycerides, and polar lipids. As development and maturation progressed, triglycerides increased substantially at the expense of mono- and diglycerides. Ungerminated seeds contained high levels of C₂₀-C₂₂ fatty acids which decreased after germination with a concomitant increase in C₁₆-C₁₈ unsaturated fatty acids. A study of the fatty acid distribution among the different classes of lipids demonstrated that 55% of the unsaturated fatty acids in the ungerminated seeds were present in the triglycerides, whereas the remainder were distributed among the mono- and diglycerides as well the other lipid classes (free fatty acids, polar lipid, and sterols). Five days after germination, the majority of these unsaturated fatty acids were found in the glyceride form. Overall the lipid classes, fatty acid composition and distribution changes during development and maturation of the French bean seed indicated that it shares many of the characteristics of soya bean development.     

Sugar-beet pulp as an alternative ingredient of barley in rabbit diets and its effect on rabbit meat

The effects of rabbit diets with four different levels of barley and sugar-beet pulp on the dressing percentage, chemical and fatty acid composition of meat from rabbits slaughtered at a liveweight of 2000 and 2500 g have been studied. Results revealed detectable (P < 0·05) effects of the total substitution of barley by sugar-beet pulp for carcass weight, dressing percentage and dry matter from animals slaughtered at a liveweight of 2000 g. No significant differences (P > 0·05) among batches were observed when slaughter weight was 2500 g. No influence of the diet on the total lipid fatty acids was found. In general, similar results were found when rabbit diets were formulated with 50% barley and 0% sugar-beet pulp, 30% barley and 0% sugar-beet pulp or 15% barley and 15% sugar-beet pulp.     

Feeding differently processed soya bean Part 3. Effect on serum constituents and bone mineralization in the chicken

The effect of feeding differently processed soya bean on serum constituents and bone mineralization in the chicken was investigated in growing chickens. The response parameters were total serum protein (TSP), albumin, globulin, albumin: globulin ratio and urea. Others were phosphorus, calcium and calcium: phosphorus ratio in the tibia and femur. The results indicated that TSP was significantly increased (P < 0.05) in the heat processed soya bean diets but decreased in the chicks fed raw soya bean diet. Albumin and globulin were not significantly affected. However, albumin: globulin ratio was significantly (P < 0.05) influenced. Serum urea was generally higher (P < 0.05) in the chicks fed processed soya bean diets. Significant (P < 0.01) decrease was observed in the total ash [%] of the bones in the chickens fed raw soya bean diet. The phosphorus [%] and Ca:P ratio in both tibia and femur were not significantly affected by dietary treatments.     

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

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

Yield, Lipid, Cholesterol and Fatty Acid Composition of Spent Hens Fed Full-Fat Oil Seeds and Fish Meal Diets

Yield, proximate and fatty acids composition of white and dark meats and whole carcasses were determined in spent hens fed flax or canola seeds, fish meal and a control diet. Live weights and percent carcass cut-up yield were not affected by the diets fed. However, hens fed flax seed diets contained significantly (P< 0.05) lower levels of cholesterol in the dark meat than the control group. The inclusion of oil seeds, in particular flax seeds in the hens diet, enriched the meats with omega-3 fatty acids (C18:3ω>3; C20:5ω3; C22:5ω3). Omega-3 fatty acids enriched poultry meats from spent hens could be useful in the development of “health oriented” further processed poultry products.     

Relationships between meat quality measurements in rabbits fed with three diets of different fat type and content

Two hundred and eighty-four, genetically similar (a three-way cross), young rabbits were fed ad libitum, from weaning, either a commercial diet (group C, ether extract 2.6%) or a diet containing vegetable fat (group V, ether extract, 9.9%) or animal fat (group A, ether extract 11.7%). A principal component (PC) analysis was performed with the variables: ultimate pH at 24 h post mortem measured in the longissimus dorsi (LD) and in the biceps femoris (BF) muscles, colour measured on the surface of the loin, fatty acid composition of perirenal fat, meat fat content of the hind leg, water holding capacity and cooking losses of the meat, and sensory variables determined by a trained panel test. The four first PC explained 62% of the total variation (27, 13, 11 and 11%, respectively). The first PC grouped the fatty acids, the second PC grouped the sensorial variables, and the third and fourth PCs grouped the pHs and the water holding capacity. The projection of the data in the first two PCs showed three separate groups of points. Animals fed with diet V were on the left side of the graph, where the variable C18:2 lies, whereas animals fed with diets A and C lay on the right side of the graph, where the saturated acids were grouped. These were slightly separated by the higher content of oleic acid in the animals fed with diet A. The second PC, where the sensorial variables were grouped, did not separate the animals fed with diets A, V and C. The diets used in this experiment had only a slight influence on the organoleptic characteristics of rabbit meat.     

Effects of previous diet and duration of soybean oil supplementation on light lambs carcass composition, meat quality and fatty acid composition

Forty Merino Branco ram lambs were used to study the effects of initial diet and duration of supplementation with a conjugated linoleic acid (CLA) promoting diet, on carcass composition, meat quality and fatty acid composition of intramuscular fat. The experimental period was 6 weeks. The experimental design involved 2 initial diets (commercial concentrate (C); dehydrated lucerne (L)), and 2 finishing periods (2 and 4 weeks) on dehydrated lucerne plus 10% soybean oil (O). Data were analysed as a 2 × 2 factorial arrangement with initial diet and time on finishing (CLA promoting) diet as the main factors. The lambs were randomly assigned to four groups: CCO; COO; LLO; LOO according to the lamb’s diet fed in each period.Lambs initially fed with concentrate showed higher hot carcass weights (11.2 vs 9.6 kg) than lambs fed initially with lucerne. The increase of the duration of finishing period reduced the carcass muscle percentage (57.4% vs 55.5%) and increased the subcutaneous fat percentage (5.67% vs 7.03%). Meat colour was affected by initial diet. Lambs initially fed with concentrate showed a lower proportion of CLA (18:2cis-9, trans-11 isomer) (0.98% vs 1.38% of total fatty acids) and most of n−3 polyunsaturated fatty acids than lambs initially fed with lucerne. Initial diet did not compromise the response to the CLA-promoting diet and the proportion of 18:2cis-9, trans-11 in intramuscular fat increased with the duration of time on the CLA-promoting diet (1.02% vs 1.34% of total fatty acids).     

Effect of feeding growing–fattening rabbits a diet supplemented with whole white lupin (Lupinus albus cv. Amiga) seeds on fatty acid composition and indexes related to human health in hind leg meat and perirenal fat

A total of 20 weaned rabbits (33 days old) (10 per treatment) were fed one of two diets that included 150 g of sunflower meal (SF)/kg of diet or 120 g of whole white lupin (WL)/kg of diet for 42 days. The WL diet contained less saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) but more monounsaturated fatty acids (MUFA) than the SF diet. The WL diet significantly decreased SFA and PUFA content, as well as the PUFA n − 6/PUFA n − 3 ratio and saturation, atherogenic and thrombogenic indexes in hind leg meat. The fatty acid composition in perirenal fat was similar to that of hind leg meat; however, significantly higher MUFA levels were observed in rabbits fed the WL diet. Thus, feeding rabbits the WL diet affected the fatty acid profile of hind leg meat and perirenal fat in a favourable manner.