Incorporation of different types of n-3 fatty acids into tissue lipids of poultry

Effect of purified fish oil supplementation on growth performance, meat quality and blood profile in broilers

The present research experimented with the view of observing the effect of supplementing purified fish oil (FO) on growth performance, organ weight, meat quality, along with blood profile of broilers. The experiment was conducted upon 1600 male Ross 308, each aged 1 day, broiler strains with an average body weight of 43.15 ± 1.35 g were randomly allotted into four dietary treatment groups where CON, basal diet; TRT1, CON + 0.05% FO; TRT2, CON + 0.10% FO; and TRT3, CON + 0.15% FO respectively. Each treatment group consisted of 20 replication pens, with each pen containing 20 broiler chicks. The 4-week long experiment was divided into two phases. The first phase (Days 7-21), the second phase (Days 22-35) and the overall (Days 7-35). On Day 21, the body weight of broilers in TRT2 and TRT3 was higher than the control. Increasing doses of purified FO supplementation showed a linear (p < 0.05) increase in body weight on Day 21. At the end of Phase 1, FO supplementation improved the body weight gain (BWG) of TRT2 and TRT3 group birds compared to CON. Increasing doses of FO supplementation increased the BWG linearly in all phases. Increasing doses of FO increased chicks' breast muscle weight with the highest value in the TRT3 group. Moreover, liver weight was linearly decreased in FO supplementation groups compared to the CON group. Abdominal fat was linearly decreased in FO supplemented groups. FO supplementation caused the lowest cholesterol and triglyceride in TRT3 than the CON group with a linear reduction. Low density lipoprotein (LDL) cholesterol was reduced by FO supplemental groups. In addition, FO supplementation increased the red blood cell (RBC) in the TRT3 group compared to the CON group. In conclusion, refined FO increased BWG, breast muscle weight and RBC and reduced cholesterol, triglycerides and LDL in broilers' blood.

Changes in the growth, ileal digestibility, intestinal histology, behavior, fatty acid composition of the breast muscles, and blood biochemical parameters of broiler chickens by dietary inclusion of safflower oil and vitamin C

BACKGROUND

The effects of safflower oil and vitamin C (Vit. C) inclusion in broiler chicken diets on the growth performance, apparent ileal digestibility coefficient "AID%" of amino acids, intestinal histology, behavior, carcass traits, fatty acid composition of the breast muscle, antioxidant and immune status for a 35-day feeding period were evaluated. A total of 300 three-day-old Ross chicks (58.25 g ± 0.19) were randomly allotted in a 2 × 3 factorial design consisting of two levels of vitamin C (0 and 400 mg/kg diet) and three levels of safflower oil (0, 5, and 10 g/kg diet).

RESULTS

An increase in the final body weight, total body weight gain, total feed intake, and the relative growth rate (P <  0.05) were reported by safflower oil and vitamin C inclusion. Dietary supplementation of safflower oil and vitamin C had a positive effect (P <  0.05) on the ingestive, resting, and feather preening behavior. Vitamin C supplementation increased (P <  0.05) the AID% of lysine, threonine, tryptophan, arginine, and valine. Safflower inclusion (10 g/kg) increased (P <  0.05) the AID% of methionine and isoleucine. Safflower oil inclusion increased (P <  0.05) the levels of stearic acid, linoleic acid, saturated fatty acids, and omega-3 fatty acids (ω-3) in the breast muscle. In contrast, the supplementation of only 10 g of safflower oil/kg diet increased (P = 0.01) the omega-3/omega-6 (ω-3/ω-6) fatty acids ratio. Vit. C supplementation increased (P <  0.05) the CAT serum levels, SOD, and GSH enzymes. Dietary supplementation of safflower oil and vitamin C improved the intestinal histology. They increased the villous height and width, crypt depth, villous height/crypt depth ratio, mucosal thickness, goblet cell count, and intra-epithelium lymphocytic lick cell infiltrations. The serum levels of IgA and complement C3 were increased (P <  0.01) by Vit. C supplementation and prominent in the 400 vit. C +  10 safflower Oil group.

CONCLUSION

A dietary combination of safflower oil and vitamin C resulted in improved growth rate, amino acids AID%, intestinal histology, welfare, immune and antioxidant status of birds, and obtaining ω-3 and linoleic acid-enriched breast muscles. The best inclusion level was 400 vit. C +  10 safflower Oil.

Serum biochemistry profile of laying hens fed diets with fish waste oil

ABSTRACT The present study aimed to evaluate increasing levels of fish waste oil in diets for laying hens on serum biochemistry profile. 192 Hisex White laying hens at 29 weeks of age were used, with water and food ad libitum. The experimental design was completely randomized consisting of eight treatments corresponding to the inclusion levels of fish waste oil (0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5%) in the diets, with four replicates of six birds each. Data collected were subjected to polynomial regression at 5% of significance. Significant differences (P<0.05) were observed in triglycerides, glucose, total cholesterol, and uric acid. These parameters presented a decrease when hens fed diets with higher level of fish waste oil. The results of the present study indicated that the inclusion of fish waste oil caused a significant effect in the serum biochemical profile of laying hens, especially in glucose, triglycerides, total cholesterol, and uric acid concentrations. The inclusion level of 3.5% of fish waste oil caused larger disequilibrium in the serum biochemical profile of laying hens.

Effect of the dietary combination of flaxseed and Ricinodendron heudelotii or Punica granatum seed oil on the fatty acid profile of eggs

The health promoting omega-3, -7, and -5 fatty acids, α-linolenic acid (ALA), docosahexaenoic acid (DHA), rumenic acid (RmA), and α-eleostearic acid (α-ESA)/punicic acid (PunA), are not currently combined in frequently consumed food items. We have evaluated the impact of supplementing laying hens' feeds with flaxseeds combined with oil derived from seeds of either Ricinodendron heudelotii, an α-ESA source, or Punica granatum, a PunA source, on the egg fatty acid profile. The supplemented diets increased the egg content in ALA, DHA, RmA, as well as α-ESA or PunA. The combination of dietary lipids did not affect the conversion rate of ALA into DHA. Hens fed on R. heudelotii or P. granatum seed oil both accumulated RmA in egg yolk, indicating an efficient conversion from the α-ESA or PunA precursors through a Δ-13 reductase activity. The accumulation of PunA in eggs was largely higher than that of α-ESA.

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

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

Effect of micronized pea seeds (Pisum sativum L.) as a substitute of soybean meal on tissue fatty acid composition and quality of broiler chicken meat

This study aimed to evaluate the effect of micronized pea seeds introduced into feed mixes for broilers on the slaughter yield, blood lipid parameters, content of fatty acids in selected tissues, and meat quality. The studies involved 150 1-day-old Ross 308 chicks split into three groups (for 42 days). The feed rations differed in terms of the source of proteins: in the control group (C), it was post-extraction soybean meal (SBM) 100%; in group I, SBM 50% and micronized peas 50%; and in group II, micronized peas only, 100%. Irradiated pea seeds added to the feed ration for chicks reduced the fattening grade of carcasses (P < 0.05). Additionally, significant improvement of blood lipid indices was recorded. The share of the irradiated pea seeds in feed mixes decreased the share of saturated fatty acids in the muscles and abdominal fat and had a positive effect on the n-6/n-3 ratio, hypocholesterolemic / hypercholesterolemic ratio, as well as the atherogenic and thrombogenic indices (P < 0.05).

Performance and Fatty Acid Composition of Adipose Tissue, Breast and Thigh in Broilers Fed Flaxseed: A Review

Interest on the enrichment of poultry meat with n-3 fatty acids has increased given its important role in human health. Flaxseed is the main sources of n-3 fatty acids, and contains between 45 to 71% of total fatty acids of the oil as α-linolenic acid. This paper reviews the plausibility of n-3 enrichment. Its focus is on the processing of flaxseed and begins by summarizing the benefits of supplementation on broiler performance. The literature on altering the FA deposition in different tissues is then reviewed, and the factors that affect the incorporation of n-3 PUFA into edible tissues of poultry are investigated. Flaxseed supplementation caused a reduction in the abdominal fat pad, and the main fatty acid deposited in the tissue is LNA. The use of fold-change analysis allowed interpreting and determining the variation of results within experiments that do not report data in similar units of measure. The fold change analysis identified three categories of desaturation response to feeding flaxseed to broilers, resulting in different values for EPA and DHA in both breast and thigh tissues: high, medium and low fold-changes. The use of flaxseed oil, whole or ground flaxseed 14 to 21 day before slaughter is recommended to poultry producers as feeding strategies to optimize n-3 enrichment, without compromising animal performance. Enriched DHA deposition could be accomplished feeding whole flaxseed.

Effect of dietary omega-3 fatty acids on red blood cell lipid composition and plasma metabolites in the cockatiel, Nymphicus hollandicus

Although dietary n-3 fatty acids have been extensively studied in poultry, they have not yet been prospectively investigated in psittacines, despite potential benefits for preventing and treating atherosclerosis, osteoarthritis, and other chronic disease processes. The objectives of this study were to investigate the incorporation of dietary n-3 fatty acids into red blood cells (RBC) and to determine the effects of supplementation of psittacine diets with fish or flax oil on plasma lipids and lipoproteins in the cockatiel. Adult cockatiels were fed a custom-formulated diet containing either 4% (wt/wt, as-fed) beef tallow (CON), 3% fish oil + 1% tallow (FSH), or 3.5% flax oil + 0.5% tallow (FLX; n = 20 per diet group). Baseline measurements were obtained for RBC fatty acid composition, triacylglycerides (TAG), and cholesterol. After 8 to 13 wk on the study diets, plasma chemistry profiles, lipoprotein density profiles, and RBC fatty acid composition were determined. At 8 wk, total plasma cholesterol was least in FSH birds (P < 0.05) and TAG concentrations were less in FSH birds than FLX birds (P < 0.05). Total n-3 fatty acids, docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid were markedly greater in the RBC of FSH birds than FLX or CON birds (P < 0.05). Alpha linolenic acid was greatest in FLX (P < 0.05). Initial and final BW, and nonlipid plasma chemistry values did not differ among diet groups. No adverse effects of dietary supplementation of cockatiels with 3.5% flax oil or 3% fish oil were observed during the 13-wk feeding period. Although fish and flax oils provided similar total n-3 PUFA to the diets, fish oil caused greater reductions in cholesterol and TAG, and greater total RBC n-3 incorporation. Thus, dietary modification of psittacine diets with long chain n-3 PUFA from fish oil appears safe and may be beneficial to these long-lived companion birds.

Influence of oils on the Taihe Silky Fowl production performances and fatty acids composition of the meat

Focus on the enrichment of eggs and poultry meat with polyunsaturated fatty acids has increased given their important roles in the human health. The inclusion of polyunsaturated fatty acids (especially n-3 fatty acids, n-3 FA) is achieved by different biological methods. The objective of this study was to investigate the effects of inclusion of different oils into the feed on the production performances and fatty acids composition of the meat in Taihe Silky Fowl. A total of 80 fowls were selected at 8 weeks and randomly divided into four groups and fed with basal diet, basal diet + 4% fish oil, basal diet + 4% soybean oil and basal diet + 4% palm oil within 3 weeks respectively. The results showed that: the fowls fed with the diet inclusion of 4% fish oil had higher total gain, average daily gain, the second and the third week average daily gain than those in control group (p< 0.05). Also, inclusion of fish oil could improve the content of C22:5 n-3 and C22:6 n-3 polyunsaturated fatty acids in the meat significantly compared with the other three groups (p < 0.01). Meanwhile, C18:3 n-3 and C18:4 n-3 polyunsaturated fatty acids were also higher than in the other three groups (p< 0.05 and 0.01). Oils Supplementation could enhance C14:0 and C16:0 (p< 0.05) level, but they did not affect the total saturated fatty acids in the meat. Compared with the control group, fish oil inclusion could lower the C18:2 n-6 level, higher the C18:3 n-6, C22:4 n-6 and C22:5 n-6 polyunsaturated fatty acids in the meat (p < 0.05). Moreover, diets supplied with 4% fish oil reduced the total n-6 polyunsaturated fatty acids level and enhanced the total n-3 polyunsaturated fatty acids level in the meat, which resulted in that the ratio of n-3/n-6 was improved, and could meet the need of human body.

Omega-3 fatty acid application reduces yolk and plasma cholesterol levels in Japanese quails

The aim of this study was to determine the effects of fish oil, rich in omega-3 fatty acids, on the cholesterol levels in egg yolk and plasma in Japanese quail. Additionally, the effects of these fatty acids on selected biochemical parameters, and yolk and quail weights were investigated. Thirty healthy laying Japanese quails were divided into two groups including control and omega-3 fatty acid treated group. Fish oil capsules were administrated orally to the quails in the omega-3 treated group every other day for 3 weeks. Yolk cholesterol level was found to be significantly lower in the omega-3 treated group compared to the control. Plasma cholesterol levels were lower; plasma calcium levels were higher at 3rd week in omega-3 fatty acid treated group than those in control. On the other hand, plasma phosphorus and glucose levels in omega-3 fatty acid group were significantly lower at 3rd week than those at the beginning of experiment. In conclusion, it was found that orally supplemented omega-3 fatty acid reduced the levels of cholesterol in egg yolk and plasma in quails.

Effects of Various Fat Sources, α-Tocopheryl Acetate, and Ascorbic Acid Supplements on Fatty Acid Composition and α-Tocopherol Content in Raw and Vacuum-Packed, Cooked Dark Chicken Meat

A factorial design was used to study the effects of dietary fat sources (beef tallow, fresh and oxidized sunflower oils, and linseed oil), alpha-tocopheryl acetate (0 and 225 mg/kg), and ascorbic acid (0 and 110 mg/ kg) supplementation on fatty acid composition, as well as on fat and alpha-tocopherol content in vacuum-packed raw and cooked meat stored at -20 degrees C. Raw meat fatty acid composition was affected by dietary fat sources and tocopheryl acetate supplementation. After cooking, meat composition was only affected by dietary fat sources. Birds fed linseed oil yielded meat rich in n-3 fatty acids, especially linolenic acid, which provides about 20% of the adequate intake for this fatty acid. Birds fed sunflower or oxidized sunflower oil produced meat rich in n-6 fatty acids, whereas those fed beef tallow resulted in meat rich in saturated and monounsaturated fatty acids. Raw and cooked dark chicken meat alpha-tocopherol content was only affected by tocopherol supplementation. Supplementation with alpha-tocopheryl acetate led to alpha-tocopherol-enriched meat, which provides about 25% of the recommended dietary allowance. Moreover, this content in vacuum-packed samples was not modified even after 7 mo of storage at -20 degrees C.

n-3 fatty acid enrichment of edible tissue of poultry: a review

There is clear evidence of the nutritional benefits of consuming long-chain n-3 PUFA, which are found predominantly in oily fish. However, oily fish consumption, particularly in the United Kingdom, is declining, as is the consumption of all meats with the exception of poultry, which has increased in consumption by 73% in the last 30 yr. This pattern, if less marked, is reflected throughout Europe, and therefore one means of increasing long-chain n-3 PUFA consumption would be to increase the long-chain n-3 PUFA content in the edible tissues of poultry. This review considers the feasibility of doing this, concentrating particularly on chickens and turkeys. It begins by summarizing the benefits to human health of consuming greater quantities of n-3 FA and the sources of n-3 PUFA in the human diet. The literature on altering the FA composition of poultry meat is then reviewed, and the factors affecting the incorporation of n-3 PUFA into edible tissues of poultry are investigated. The concentration of alpha-linolenic acid (ALA) in the edible tissues of poultry is readily increased by increasing the concentration of ALA in the birds' diet (particularly meat with skin, and dark meat to a greater extent than white meat). The concentration of EPA in both white and dark meat is also increased when the birds' diet is supplemented with EPA, although supplementing the diet with the precursor (ALA) does not result in a noticeable increase in EPA content in the edible tissues. Although supplementing the birds' diets with relatively high concentrations of DHA does result in an increased concentration of DHA in the tissues, the relationship between dietary and tissue concentrations of DHA is much weaker than that observed with ALA and EPA. The impact that altering the FA composition of edible poultry tissue may have on the organoleptic and storage qualities of poultry products is also considered.

Cholesterol and n-3 and n-6 fatty acid content in eggs from laying hens fed with red crab meal (Pleuroncodes planipes)

Red crab (Pleuroncodes planipes) is a marine crustacean that represents an abundant resource that has not been properly used. The aim of this study was to evaluate the effects on cholesterol and n-3 and n-6 FA content in eggs when red crab meal (RCM) was included in laying hen rations. Ninety White Leghorn laying hens were randomly distributed into 3 treatments: control (0%RCM), 3% red crab meal (3%RCM), and 6% red crab meal (6%RCM) for 3 wk. Cholesterol and linoleic (LA), alpha-linolenic (ALA), arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids were analyzed by gas chromatography. Performance parameters and cholesterol content were not different among treatments (P > 0.05). Total lipids were different in the control group and 6%RCM (9.0 and 9.4% respectively) compared with 3%RCM (10.9%). With 3%RCM and 6%RCM, the levels of all fatty acids analyzed were higher than in the control. Diets with 3 and 6% RCM doubled the content of ALA (16.4 and 15.4 mg/100 g of egg, respectively). Eicosapentaenoic acid was lowest in 0%RCM (6 mg/100 g of egg) compared with 3%RCM (13 mg/100 g) and 6%RCM (17 mg/100 g). Similar results were obtained for DHA (56, 133, and 246 mg/100 g of egg). Linoleic acid and AA were highest (1,211 and 228 mg/100 g, respectively) with 3%RCM and with 6%RCM (1,151 and 200 mg/100 g, respectively) vs. control (890 and 163 mg/100 g). The ratio of n-6 to n-3 FA was 3 times lower with 6%RCM than in the control. It was concluded that inclusion of red crab meal in laying hen rations at levels of 3 and 6% (P < 0.05) increased the n-3 and n-6 fatty acids content in eggs.

Severity of Atherosclerosis in Parrots in Relation to the Intake of α-Linolenic Acid

Atherosclerosis is a common disease among parrots, but little is known about possible risk factors. Important risk factors in humans are an elevated plasma cholesterol concentration and increased platelet aggregation; high intakes of polyunsaturated fatty acids have beneficial effects. In this study, we tried to establish a relationship, if any, between dietary fatty acids and the severity of atherosclerosis in parrots. We collected dead parrots and scored the degree of atherosclerosis in the beginning of the aorta and the brachiocephalic arteries. It was not possible to assess the intake of fatty acids with food questionnaires so fatty acid composition of adipose tissue and breast muscle had to be used as an index of the dietary fatty acid composition. In all, 202 birds were collected. Gender was not related with atherosclerosis, but the degree of atherosclerosis increased with age and among the various species; African grey parrots appeared to be the most susceptible. The contents of linoleic acid in breast muscle or adipose tissue were not associated with the severity of atherosclerosis. For the relative percentage of alpha-linolenic acid in either breast muscle (P = 0.09; n = 175) or adipose tissue (P = 0.056; n = 21), a borderline significant relation with the degree of atherosclerosis was found. Parrots without atherosclerosis had significantly higher levels of alpha-linolenic acid than did the other animals. On the basis of these data, we suggest tentatively that a high dietary intake of alpha-linolenic acid protects against the development of atherosclerosis in parrots.

n-3 enrichment of chicken meat. 1. Use of very long-chain fatty acids in chicken diets and their influence on meat quality: fish oil

We assessed the effect of a diet supplemented with fish oil (FO) on the performance, fatty acid (FA) composition, quality, and sensory traits of broiler meat. Diets enriched with 0, 2, or 4% FO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to the birds throughout a 38-d growth period. T3 was replaced by a mixture of FO, linseed oil (LO), and T (1, 3, and 4% respectively) for 1 wk (T4) or 2 wk (T5) before slaughter. Meat quality, taste, and FA profile were determined. Higher final weights were recorded for birds fed T3, although feed efficiency was not affected. Other performance or objective meat quality parameters did not show significant differences among treatments. High FO concentrations decreased the saturated and monoenoic FA contents in the thigh samples. The amount of polyunsaturated fatty acids (PUFA) increased when added to the diet (FO diets), mainly as long-chain n-3 FA [eicosapentaenoic fatty acid (EPA), docosapentaenoic fatty acid (DPA), and docosahexaenoic fatty acid (DHA)]. On the other hand, levels of total n-6 FA resulted in slight changes, mostly in linoleic acid (LA). By replacing the FO diet with the experimental mixture (T4, T5), the n-3 and n-6 FA contents increased, mainly in the form of linolenic acid and LA, respectively, only 1 wk later. After 1 wk of T4, the DHA levels in chicken decreased. Sensory panelists could not identify the meats from T4 and T5 as being different from the control diet (T1).

Composição em ácidos graxos da gordura na carcaça de frangos de corte sob dietas com diferentes fontes de energia

Avaliaram-se os níveis de energia metabolizável normalmente utilizados nas rações de frangos de corte, obtidos pela inclusão de óleos vegetais (soja, canola e palma) e seus efeitos sobre o perfil de ácidos graxos da pele e dos músculos da coxa e do peito, levando-se em consideração a linhagem e o sexo. Foram utilizados 2400 pintos de um dia, machos e fêmeas, das linhagens comerciais Hubbard e Avian Farms. As aves receberam ração inicial e final com níveis de energia metabolizável de 3050 e 3150kcal/kg, respectivamente, obtidos pela inclusão dos óleos vegetais, fornecedores de ácidos graxos, inclusive "ômega-3". Utilizou-se um delineamento inteiramente ao acaso em um arranjo fatorial com 16 tratamentos (4 rações × 2 sexos × 2 linhagens) com duas repetições cada. Diferenças entre médias foram testadas pela dms. Não houve efeito significativo da inclusão de óleos na ração sobre o perfil de ácidos graxos na carcaça. O mesmo ocorreu quanto ao efeito de sexo e de linhagem.

n-3 enrichment of chicken meat using fish oil: alternative substitution with rapeseed and linseed oils

Two sequential experiments were conducted to assess the effect of replacing a fish oil diet with vegetable oil diets on broiler chicken performance and fatty acid (FA) composition and sensory traits of broiler meat. A diet enriched with 8.2% fish oil (FO) was fed to the birds throughout the 5-wk growth period (T1), the same basal diet being supplemented with 8.2% linseed oil (LO, Experiment 1) or rapeseed oil (RO, Experiment 2) in three different periods: the last week before slaughtering at 35 d (T2), the last 2 wk (T3), and throughout the experiment (T4). A sensory evaluation of the meat was carried out and its FA profile was determined. Performance parameters were not significantly different among treatments. Removing FO resulted in lower values of saturated and higher n-6 FA content, the latter because of the increase in linoleic acid in both experiments. The amounts of long-chain n-3 polyunsaturated fatty acids (PUFA) were significantly depressed when FO was replaced. However, replacing FO by LO resulted in minimal effects on total n-3 FA, due to the increase in linolenic acid. The substitution of FO by RO resulted in a decrease in the n-3 FA content, whereas levels of monounsaturated FA (MUFA) increased in direct relation to the larger amounts of oleic acid in the diet. Sensory panelists scored as unacceptable those meats from T1 in both experiments. Replacing 1 (T2) or 2 (T3) wk FO with vegetable oil clearly resulted in the improved sensory quality of meat.

Dietary fish oil alters specific and inflammatory immune responses in chicks

Two experiments were designed to determine the effects of dietary (n-3) fatty acids and grain source on the growth-suppressive effects of the inflammatory response and indices of specific immunity. In Experiment 1, chicks were fed diets containing 0.5, 1, or 2 g/100 g of either corn oil or fish oil. In Experiment 2, chicks were fed diets containing up to 2 g/100 g of either fish oil, linseed oil or corn oil as the source of dietary fat, in either cereal grain- or corn-based diets. In each experiment, subsets of chicks within each dietary treatment were either vaccinated with infectious bronchitis virus (IBV) vaccine, injected with Salmonella typhimurium lipopolysaccharide (LPS), heat-killed Staphylococcus aureus, or remained noninjected. Increasing dietary fish oil, but not corn oil increased body weight and lessened the growth-suppressing effect of heat-killed S. aureus or S. typhimurium LPS. Increasing the concentration of dietary fish oil decreased febrile response, circulating hemopexin and metallothionein concentrations. Dietary fish oil resulted in decreased release relative to dietary corn oil of interleukin-1 by peritoneal macrophages. Although IBV titers were not significantly affected by dietary oil treatment, phytohemagglutination-induced wattle swelling was greater among chicks fed fish oil. In Experiment 2, the modulating effects of fish oil on the immune system were dependent on the type of grain used in the diet, with fish oil/cereal diets resulting in greater cell-mediated immunity and lower indices of inflammation than fish oil/corn diets. Inclusion of increasing amounts of fish oil in the diet improved performance, decreased indices of the inflammatory response and either improved or did not change indices of the specific immune response of growing chicks.

Effects of dietary fat sources on lipid metabolism in growing chicks (Gallus domesticus)

The effect of dietary fat sources with different degrees of unsaturation and double bond positioning on lipid metabolism was studied in growing chicks. Four-week-old chicks were given semi-purified diets containing 6% palm oil (PLO), 6% safflower oil (SFO), 3% safflower oil and 3% linseed oil (SFO + LNO), 6% linseed oil (LNO), or 3% linseed oil and 3% fish oil (LNO + FO) with 0.5% cholesterol supplementation. Cholesterol ester content in the liver and serum of chicks fed PLO diet was significantly higher than that of other diet groups. Liver triacylglycerol and free cholesterol contents were significantly decreased in chicks fed a diet containing n-3 fatty acids (i.e., linseed oil or fish oil). Serum triacylglycerol level was also decreased by feeding the LNO or LNO + FO diet. The activity of serum lecithin-cholesterol acyltransferase was not affected by dietary treatments. Fecal neutral steroid excretion was significantly increased in the LNO+FO diet group as compared with the SFO + LNO or LNO diet groups. With the increase in linseed oil levels, the levels of C18:2n6 and C20:4n6 fatty acids in tissue lipids decreased, but C18:3n3 and C20:5n3 were gradually increased. The levels of longer chain n-3 fatty acids (i.e., C20:5n3 or C22:6n3) in chicks fed a diet containing fish oil (LNO + FO diet) were significantly increased compared to those fed linseed oil with a corresponding level. These results demonstrated that dietary fat enriched with alpha-linolenic acid and longer chain n-3 fatty acids have stronger effects on lowering serum lipid levels than dietary fat composed of either saturated, or n-6 fatty acids, but both n-3 fatty acids sources show differing effects on the deposition of longer chain n-3 fatty acids into tissue lipids.

Effects of dietary fatty acid pattern on melting point and composition of adipose tissues and intramuscular fat of broiler carcasses

Soybean oil (SO), rapeseed oil (RO), or two commercial fat products (FP1, FP2) were incorporated at 3.5% levels into four different corn-soybean meal mash broiler diets. Each of the four diets was fed to five replicates (pens) of broiler chickens for 42 d. After slaughtering the birds, samples of the abdominal fat, subcutaneous fat, and fat extracted from the thigh and the breast portion were collected from 16 birds per treatment. The fat samples were analyzed for their fatty acid composition using gas chromatography and the melting point of the abdominal fat was recorded. The results showed that the abdominal and subcutaneous fat had very similar fatty acid patterns and differed significantly from the composition of the fat extracted from breast and thigh. The different dietary treatments caused significant changes in the fatty acid patterns for all analyzed tissues, although the differences were more pronounced for the adipose tissues. Overall, the adipose tissues contained more polyunsaturated and less saturated fatty acids than the fat from the breast and thigh portions. The melting point of the abdominal fat was significantly altered by the use of different dietary fats: RO gave a lower melting point than SO and FP1; the highest values were recorded for FP2. The data presented here indicate that the selection of certain dietary fat sources has a major impact on the composition and the melting point of broiler adipose tissues. The effect on the fatty acid composition of meat portions, however, is limited.

Effect of different dietary supplemental fats and oils on the tissue fatty acid composition and growth of female broilers

1. A study was undertaken to examine the effect of supplementation of diets with fats of different chain length and degree of unsaturation on the performance, carcase characteristics and tissue fatty acid composition of broilers. 2. Three hundred and sixty 19-day-old female broilers were fed on diets containing supplemental fat/oil (50 g/kg) in the form of beef tallow (BT) (diet T-T), soyabean oil (SBO) (diet S-S), rapeseed oil (RSO) (diet R-R), marine oil (MO) (diet M-M) or binary mixtures (0.5:0.5 w/w) of these lipids (diets T-S, T-R, T-M, S-R, S-M, and R-M) to 54 d of age. Food intake, live weight, plucked weight and the lipid concentration and fatty acid composition of abdominal fat pad, liver and breast muscle were measured. 3. Food intake, plucked weight and live weight were greatest for diet T-T and lowest for diet R-R. Food conversion ratio was poorest for birds fed on diets containing BT. Lipid concentration in abdominal fat pad was significantly higher in birds fed on diets containing SBO. Liver lipid concentration was significantly reduced by diets containing RSO. 4. Abdominal fat pad fatty acid profile was most readily altered by dietary fatty acids. There was a strong correlation between dietary fatty acid composition and tissue fatty acid composition for all fatty acids except C14:0, C20:0, C20: 2n-6 and C20: 4n-6. The tissue P/S ratio ranged from 0.40 for diet T-T to 1.40 for diet S-S. The n-6/n-3 ratio was significantly increased by the inclusion of SBO and decreased by the inclusion of MO. 5. Liver fatty acid profile was least modified by dietary fatty acids. There was an inverse relationship between liver and dietary C20:4n-6 concentration. Tissue C18:2n-6 and C20:4n-6 were highly correlated, suggesting significant interconversion by delta-6 desaturase in this tissue. The n-6/n-3 ratio was significantly increased by inclusion of SBO and significantly decreased by the inclusion of MO. 6. In breast muscle MO-based diets increased the proportion of n-3 PUFA at the expense of n-6 PUFA. The tissue concentrations of C18:1n-9, C18:2n-6, C20:1n-9, C20:5n-3, C22:5n-3 and C22:6n-3 were strongly correlated with dietary fatty acid composition. Muscle and diet P/S and n-6/n-3 ratios were highly correlated.