Evaluating the impact of organic chromium on hepatic phospholipid fatty acid molecular species, transcription of genes associated with lipid metabolism and oxidative status in broiler chickens fed flaxseed.

Flaxseed is a rich source of α-linolenic acid (ALA, 18:3 n-3) and can be used to enrich chicken tissues with n-3 fatty acids (FA). However, antinutritional factors in flaxseed compromise the live performance of birds coupled with increased oxidative stress. Chromium (Cr) is a trace element with antioxidant properties. It is hypothesized that Cr supplementation will affect the hepatic total lipid profile, phospholipid n-3 and n-6 FA molecular species, lipid oxidation products, and transcription of genes associated with lipid metabolism in broiler chickens fed flaxseed. Ninety (n = 90), day-old Cornish cross chicks were fed a corn-soybean meal-based diet containing 0% flaxseed (CTR), 10% flaxseed (FLAX), and FLAX + 0.05% organic Cr (FLAXCr) for 42 d. The chicks were kept in 18 pens with 5 chicks per pen. For all response variables, the effect of dietary treatments were compared separately using SAS 9.4. P values were considered significant at ≤0.05. Total lipids, saturated FA, long-chain (≥20C) n-6 FA were reduced while total n-3 FA and long-chain n-3 FA were higher in the liver of FLAX and FLAXCr than CTR (P < 0.05). Hepatic phosphatidylcholine (PC) and phosphatidylethnolamine (PE) n-3 species (36:5, 38:6) were higher in FLAX and FLAXCr compared to CTR (P < 0.05). On the contrary, n-6 species in PC (36:4, 38:4) and PE (38:4) were lower in FLAX and FLAXCr compared to CTR (P < 0.05). Addition of Cr to a flaxseed-containing diet led to an increase in PE 36:4 (P < 0.05). A decrease in the transcription of ELOVL6 gene involved in de novo lipid synthesis was observed in FLAXCr (P = 0.01). An increase in the transcription of genes involved in FA oxidation (ACAA2, ACOX1) was observed in FLAX compared to FLAXCr (P = 0. 05; P = 0.02). A trend for a decrease in the transcription of FADS2 and HMGCS1 was observed in FLAXCr than CTR and FLAX (P = 0.06; 0.08). Transcription of other genes involved in de novo lipid synthesis (FASN, PPARA), FA oxidation (CPT1A, CPT2, ACAA1), and oxidative stress response (GPX1, NQO11, GSTA2, SLC40A1, NFE2L2) were not affected by the diets (P > 0.05). Lipid peroxidation products measured as thiobarbituric acid reactive substances (TBARS) in liver was reduced in FLAXCr than CTR (P < 0.05) and was not different from FLAX (P > 0.05). Serum cholesterol and aspartic aminotransferase were reduced in FLAX and FLAXCr compared to CTR (P < 0.05). The serum glucose level was decreased in FLAX compared to CTR (P < 0.05) and a trend in decrease was noticed in FLAXCr vs. CTR (P = 0.10). Serum TBARS were higher in CTR and FLAXCr compared to FLAX (P < 0.05). In conclusion, flaxseed supplementation enhances total and long-chain n-3 FA while reducing total lipids, saturated, and n-6 FA in the liver. Supplementing Cr along with flaxseed increased n-6 FA species in the hepatic PE and decreased the transcription of genes involved in FA oxidation and lipid synthesis.

Evaluating the impact of organic chromium with flax seed in broiler diets: effects on production performance, breast muscle pathology, and meat quality aspects.

The study investigated the impact of organic chromium (Cr) and flax seed supplementation on live performance, carcass yield, muscle lipid profile, histopathological aspects, and meat quality parameters in broilers. Ninety (n = 90), day-old Cobb chicks were fed a corn-soybean meal-based diet containing 0% flax seed (Control), 10% flax seed (Diet 1) and Diet 1 + 0.05% organic Cr (Diet 2). The experiment was a completely randomized design and chicks were placed in 6 pens with 5 chicks per each pen. Pen was the experimental unit for production performance and bird collected from each pen was considered as experimental unit for all other analysis. On d 43, 45, and 48, one bird per pen were euthanized. A one-way ANOVA was performed with diet as the main factor and significance was set at P < 0.05. Significant differences between each treatment were analyzed by GLM Lean Square Method and Tukey's Honestly Significant Difference test. Weight gain and feed:gain was determined at d (1-11), (12-21), and (22-42). For all response variables, the effects among dietary treatments were compared using ANOVA separately using SAS 9.4. P -values were considered significant at ≤0.05. At d 22, Diet 1 and Diet 2 birds had lower BW and feed:gain than Control (P < 0.05). At d 42, Diet 2 birds were higher in BW with improved feed:gain when compared to Diet 1 (P < 0.05) but were not different from Control (P > 0.05). The overall weight gain was higher in Diet 2 and Control compared to Diet 1 (P < 0.05) and overall feed:gain was the highest in Control than the experimental diets (P < 0.05). Histopathological changes in breast muscle including floccular/vacuolar degeneration, fibrosis, lipidosis, interstitial inflammation, and muscle lysis were less pronounced in Diet 1 compared to Diet 2 (P < 0.05). Breast muscle total fat and cholesterol was lower in Diet 1 compared to Control (P < 0.05). Diet 1 and Diet 2 increased (>2-5 fold) total and long chain (≥20C) n-3 fatty acids (FA) in the breast muscle (P < 0.05) compared to Control. Lipid peroxidation products measured as thiobarbituric acid reactive substances were lower in the breast muscle of Diet 1 and Diet 2 compared to Control (P < 0.05). Phospholipid n-3 FA molecular species in phosphatidylcholine (PC) 36:5, 38:6, and phosphatidylethanolamine (PE) 36:5 were higher in breast muscle of Diet 1 than Control (P < 0.05) and was not different from Diet 2 (P > 0.05). A decrease in n-6 FA species (36:4 and 38:4) was observed in PC and PE of Diet 1and Diet 2 compared to Control (P < 0.05). Drip loss values were reduced in Diet 1 and Diet 2 versus Control (P < 0.05). As consumer demand for n-3 FA-rich poultry products are on the rise, Cr may serve as a feed supplement that could be used in broilers fed flax seed-containing diets for enriching edible tissues with n-3 FA, while enhancing production performance.

Hatching egg polyunsaturated fatty acids and the broiler chick.

Transgenerational effects of certain nutrients such as essential fatty acids are gaining increased attention in the field of human medicine and animal sciences as a new tool to improve health and animal performance during perinatal life. Omega-3 (n-3) and omega-6 (n-6) fatty acids are denoted by the position of the first double bond from methyl end of the hydrocarbon chain. Alpha-linolenic acid (18:3 n-3) and linoleic acid (18:2 n-6) are essential n-3 and n-6 fatty acids and cannot be synthesized by the vertebrates including chickens. Alpha-linolenic acid and linoleic acid are the parent fatty acids of long chain (> 20-22C) n-3 and n-6 polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (20:5 n-3, EPA), docosapentaenoic acid (22:5 n-3/or 22:5 n-6, DPA), docosahexaenoic acid (22:6 n-3, DHA) and arachidonic acid (20:4 n-6). As components of cell membrane phospholipids, PUFA serves as precursors of eicosanoids, act as ligands for membrane receptors and transcription factors that regulate gene expression and are pivotal for normal chick growth and development. Considering the role of egg lipids as the sole source of essential fatty acids to the hatchling, dietary deficiencies or inadequate in ovo supply may have repercussions in tissue PUFA incorporation, lipid metabolism, chick growth and development during pre and early post-hatch period. This review focus on studies showing how maternal dietary n-3 or n-6 fatty acids can lead to remodeling of long chain n-3 and n-6 PUFA in the hatching egg and progeny chick tissue phospholipid molecular species and its impact on chick growth and PUFA metabolism during early life.

Docosahexaenoic acid (22:6 n-3)-rich microalgae along with methionine supplementation in broiler chickens: effects on production performance, breast muscle quality attributes, lipid profile, and incidence of white striping and myopathy.

The effect of docosahexaenoic acid (DHA, 22:6 n-3)-rich microalgae and methionine (Met) supplementation on production performance, incidence of breast muscle white striping (WS), and pathology, lipid profile, and meat quality aspects in broiler chickens was investigated. The hypothesis tested was that feeding Met and n-3 fatty acid (FA)-rich diet enhances muscle n-3 FA content and meat quality while attenuating breast muscle WS and myopathy in broiler chickens. One hundred and forty four (n = 144) 10-day-old Cornish cross chicks were fed a corn-soybean meal-based diet containing 0% microalgae (control), 2% microalgae (diet 1), and diet 1 + 100% more National Research Council requirement of Met (diet 2) up to day 42 of growth. All diets were isocaloric and isonitrogenous. The chicks were kept in 6 pens with 8 chicks per replicate pen. Feed consumption and feed efficiency were calculated on day 21 and 42. On day 43, 3 chicks per pen (n = 18/treatment) were euthanized. The breast muscle (pectoralis major) was visually scored for muscle WS (1 = no striping, 2 = mild, 3 = severe) and was subjected to histopathology. Breast muscle lipid profile (total lipids, FA composition, cholesterol, lipid oxidation products), quality (moisture, color, drip loss, shear force, cook loss, pH), and chemical characterization (protein, minerals) were recorded. A one-way analysis of variance was carried out with diet as the main factor and significance was set at P < 0.05. The incidence of muscle WS was lower (P < 0.02) for control vs. diet 2 and a trend for reduction in WS was observed in birds fed diet 1 vs. control (P = 0.09). Histopathological changes consisted of floccular or vacuolar degeneration, fibrosis, lipidosis, interstitial inflammation, and lysis of fibers, and were minimal in diet 2 when compared to control (P < 0.05). The total lipid content was lowest in birds fed diet 1 (P < 0.05). Total n-3 and total long chain (≥20C) n-3 FA were highest in the breast muscle of diet 2 birds (P < 0.05). Muscle drip loss and shear force were highest in diet 2 (P < 0.05). Meat color (a∗, redness) was reduced (P < 0.05) and a trend for reduction in b∗ (yellowness) was observed in diet 2 (P = 0.07). No effect of diet on body weight gain, feed efficiency, breast muscle yield, pH, moisture, lipid oxidation products, cook loss, minerals (Ca, P, Mg, Na), cholesterol, or protein content was observed (P > 0.05). The results demonstrated a significant effect of DHA-rich microalgae along with Met supplementation in reducing the incidence of breast muscle striping and myopathy, while enriching meat with n-3 FA. However, inclusion of Met in microalgae-based diets could influence meat tenderness and color.

Choline supplementation alters egg production performance and hepatic oxidative status of laying hens fed high-docosahexaenoic acid microalgae.

The purpose of the current study was to investigate the effect of choline as a means of increasing docosahexaenoic acid (22:6 n-3, DHA) deposition in egg yolks of hens fed a high-DHA microalgae product. Fifty-six, 26-wk-old, White Leghorn hens were kept in individual cages and randomly allocated to 1 of 4 dietary treatments, each with 7 replicate groups of 2 hens (n = 7 per treatment). The experimental diets were corn and soybean meal based, with 0% microalgae (control), 1% microalgae and no additional choline chloride (Alg), and Alg plus choline chloride at 0.1% (Ch0.1) and 0.2% (Ch0.2). The feeding trial lasted 16 wk. The data were fit as a general linear mixed model to generate least square means in response to diet. Variables measured multiple times during the study were fit as repeated measures. Using orthogonal contrasts, Alg was compared to control, and Ch0.1 and Ch0.2 were compared separately to Alg. Ch0.1 increased hen day egg production (P < 0.05) and Haugh unit (P < 0.05), and reduced feed conversion ratio (P < 0.05) compared to Alg, but Ch0.2 did not. Alg increased egg DHA (P < 0.001), phosphatidylethanolamine (P < 0.05), and phosphatidylcholine (P < 0.001) compared to control, but Ch0.1 or Ch0.2 had no effect compared to Alg (P > 0.05). In the liver, Alg increased lipid peroxidation products compared to control (P < 0.01), and Ch0.1 reduced them compared to Alg (P < 0.01). Both Ch0.1 and Ch0.2 increased hepatic concentrations of γ- (P < 0.05; P < 0.001) and α-tocopherol (P < 0.01; P < 0.001), and Ch0.1 increased γ-tocopherol concentration in eggs compared to Alg (P < 0.05). The results from the current study suggest that supplemental choline chloride in hen diets containing microalgae can improve production performance and egg quality, and protect the liver from oxidative stress.

2,4-Thiazolidinedione in Well-Fed Lactating Dairy Goats: I. Effect on Adiposity and Milk Fat Synthesis.

Background: In a prior experiment, treatment of goats with the putative PPARγ agonist 2,4-thiazolidinedione (2,4-TZD) did not affect milk fat or expression of milk-fat related genes. The lack of response was possibly due to deficiency of vitamin A and/or a poor body condition of the animals. In the present experiment, we tested the hypothesis that PPARγ activation affects milk fat synthesis in goats with a good body condition and receiving adequate levels of vitamin A. Methods: Lactating goats receiving a diet that met NRC requirements, including vitamin A, were injected with 8 mg/kg BW of 2,4-TZD (n = 6) or saline (n = 6; CTR) daily for 26 days. Blood metabolic profiling and milk yield and components were measured including fatty acid profile. Expression of genes related to glucose and lipid metabolism was measured in adipose tissue and in mammary epithelial cells (MEC). Size of adipocytes was assessed by histological analysis. Results: NEFA, BHBA, and fatty acids available in plasma decreased while glucose increased in 2,4-TZD vs. CTR. Size of cells and expression of insulin signaling and glucose metabolism-related genes were larger in 2,4-TZD vs. CTR in adipose tissue. In MEC, expression of SCD1 and desaturation of stearate was lower in 2,4-TZD vs. CTR. Conclusions: Overall data revealed a lack of PPARγ activation by 2,4-TZD and no effect on milk fat synthesis despite a strong anti-lipolysis effect on adipose tissue.

Flaxseed and Carbohydrase Enzyme Supplementation Alters Hepatic n-3 Polyunsaturated Fatty Acid Molecular Species and Expression of Genes Associated with Lipid Metabolism in Broiler Chickens.

Flaxseed is rich in α-linolenic acid and is used in broiler chicken diets to enrich tissues with n-3 fatty acids (FA). However, non-starch polysaccharides (NSP) in flaxseed decreases nutrient digestibility and limits the availability of n-3 FA. Addition of carbohydrase enzymes to flaxseed-based diets can decrease the anti-nutritive effects of NSP. We hypothesized that flaxseed and enzyme supplementation affect lipid content and alter expression of genes related to lipid metabolism in broiler liver. Five day-old broiler chicks were fed a corn-soybean basal diet with 0% flaxseed, a basal diet with 10% of flaxseed, or 10% flaxseed + 0.05% enzyme diet up to day 42 of growth. Total lipids, including long-chain (≥20C) n-3 FA and monounsaturated FA, were increased in flax-fed broiler livers. Enzyme addition reduced arachidonic acid and total long chain n-6 FA. These changes were similarly reflected in phosphatidylcholine lipid species. Dietary flax and enzyme treatments up-regulated PPARα target genes CPT1A and ACOX1 while reducing expression of de novo FA synthesis-related genes. This study concludes that flaxseed and enzyme supplementation in broiler diets enhances LC n-3 FA species, while reducing n-6 FA species in hepatic phospholipids (PL). Flaxseed-based diets changes the expression of genes involved in FA lipid metabolism without affecting growth or production performance in broilers.

Histology of the Ovary of the Laying Hen (Gallus domesticus).

The laying hen (Gallus domesticus) is a robust animal model for epithelial ovarian cancer. The use of animal models is critical in identifying early disease markers and developing and testing chemotherapies. We describe the microscopic characteristics of the normally functioning laying hen ovary and proximal oviduct to establish baselines from which lesions associated with ovarian cancer can be more readily identified. Ovaries and oviducts were collected from 18-month-old laying hens (n = 18) and fixed in 10% neutral buffered formalin. Hematoxylin- and eosin-stained sections were examined by light microscopy. Both post-ovulatory follicular regression and atresia of small follicles produce remnant clusters of vacuolated cells with no histological evidence that scar tissue persists. Infiltrates of heterophils are associated with atresia of small follicles, a relationship not previously documented in laying hen ovaries. Because these tissues can be mistaken for cancerous lesions, we present a detailed histological description of remnant Wolffian tissues in the laying hen ovary. Immunohistochemical staining for pancytokeratin produced a positive response in ovarian surface epithelium and staining for vimentin produced a positive response in granulosa cells of follicles. Epithelial cells lining glands of the remnant epoöphoron had a positive response to both pancytokeratin and vimentin, a result also observed in women.

Effect of whole flax seed and carbohydrase enzymes on gastrointestinal morphology, muscle fatty acids, and production performance in broiler chickens.

Flax seed is a rich source of α-linolenic acid (18:3 n-3). Feeding broiler birds flax seed can increase n-3 fatty acids in meat tissues. However, non-starch polysaccharides in flax seed decrease nutrient digestibility and can have a negative impact on bird performance and muscle fatty acid content. Addition of carbohydrase enzymes to flax-based broiler diets can decrease the anti-nutritive effects of non-starch polysaccharides. An experiment was conducted to investigate on the effect of flax seed and carbohydrase enzyme foregut morphology, muscle tissue, fatty acids, and bird performance. A total of 112 five-day-old broiler chicks were assigned to one of four treatments: Flax10 (corn-soybean meal basal diet adjusted for 10% flax), Flax15 (basal diet adjusted for 15% flax), Flax10E (Flax10 + 0.05% enzyme), and Flax15E (Flax 15 + 0.05% enzyme). Addition of enzyme led to large increases in villi height and villi width in the jejunum of birds fed Flax10 and increases in crypt depth in the jejunum of birds fed Flax15 (P < 0.05). The ratio of villi height to crypt depth was larger in the duodenum and jejunum of birds fed Flax10E when compared to Flax10 (P < 0.05). Feeding the Flax15 diet led to a significant decrease in total lipids in breast muscle compared to Flax10 (P < 0.05). The effect of level of flax or enzyme supplementation was minimal on the fatty acids measured in breast muscle except for total n-6 fatty acids which was higher (P < 0.05) in Flax15 when compared to Flax10. In thigh muscle, stearic acid, arachidonic acid, and total n-6 fatty acids were higher in birds fed Flax15 vs. Flax10. Feeding Flax15 led to a reduction in dry matter of excreta when compared to Flax10 (P < 0.05). There were no differences in BW, average daily gain, or feed consumption during the starter or grower phase due to flax level or enzyme addition (P > 0.05).

Egg quality, fatty acid composition and immunoglobulin Y content in eggs from laying hens fed full fat camelina or flax seed.

BACKGROUND: The current study was conducted to evaluate egg quality and egg yolk fatty acids and immunoglobulin (IgY) content from laying hens fed full fat camelina or flax seed. METHODS: A total of 75, 48-week-old Lohman brown hens were randomly allocated to 3 treatments, with 5 replicates containing 5 laying hens each replicate. The hens were fed corn-soybean basal diet (Control), or Control diet with 10 % of full fat camelina (Camelina) or flax seed (Flax) for a period of 16 wk. Hen production performance egg quality, egg yolk lipids, fatty acids and IgY were determined every 28 d during the experimental period. RESULTS: Egg production was higher in hens fed Camelina and Flax than in Control hens (P < 0.05). Egg weight and albumen weight was lowest in eggs from hens fed Camelina (P < 0.05). Shell weight relative to egg weight (shell weight %), and shell thickness was lowest in eggs from hens fed Flax (P < 0.05). No difference was noted in Haugh unit, yolk:albumen ratio, and yolk weight. Significant increase in α-linolenic (18:3 n-3), docosapentaenoic (22:5 n-3) and docoshexaenoic (22:6 n-3) acids were observed in egg yolk from hens fed Camelina and Flax. Total n-3 fatty acids constituted 1.19 % in Control eggs compared to 3.12 and 3.09 % in Camelina and Flax eggs, respectively (P < 0.05). Eggs from hens fed Camelina and Flax had the higher IgY concentration than those hens fed Control diet when expressed on a mg/g of yolk basis (P < 0.05). Although the egg weight was significantly lower in Camelina-fed hens, the total egg content of IgY was highest in eggs from hens fed Camelina (P < 0.05). CONCLUSIONS: The egg n-3 fatty acid and IgY enhancing effect of dietary camelina seed warrants further attention into the potential of using camelina as a functional feed ingredient in poultry feeding.

Nutrition and metabolism in poultry: role of lipids in early diet.

Modern strains of broiler chickens are selected for fast growth and are marketed anywhere from 36 to 49 days after a 21-day incubational period. For a viable healthy chick, all the necessary nutrients required for growth and development must be provided by the hen through the fertilized egg. The current feeding strategies for improved growth, health and productivity are targeted towards chicks after hatching. Considering the fact that developing chick embryo spends over 30 % of its total life span inside the hatching egg relying on nutrients deposited by the breeder hen, investigations on nutritional needs during pre-hatch period will improve embryonic health, hatchability and chick viability. In this context, investigations on hatching egg lipid quality is of utmost importance because, during incubation, egg fat is the major source of energy and sole source of essential omega-6 (n-6) and omega-3 (n-3) fatty acids to the chick embryo. Due to the unique roles of n-3 and n-6 fatty acids in growth, immune health, and development of central nervous system, this review will focus on the role of early exposure to essential fatty acids through maternal diet and hatching egg and its impact on progeny in meat-type broiler chickens.

A feeding study to assess nutritional quality and safety of surimi wash water proteins recovered by a chitosan-alginate complex.

Soluble proteins from surimi wash water (SWW) precipitated using a chitosan-alginate (Chi-Alg) complex and recovered by centrifugation were freeze-dried. Analysis showed that SWW proteins (SWWP) had a crude protein content of 73.1% and a high concentration of essential amino acids, for example, 3% histidine, 9.4% lysine, 3.7% methionine, and 5.1% phenylalanine. In a rat-feeding trial, SWWP as a single protein source showed higher (P < 0.05) modified protein efficiency ratio and net protein ratio than the casein control. Blood chemistry analysis revealed no deleterious effect from the full protein substitution or the chitosan in SWWP. Therefore, this preliminary study revealed that proteins recovered from SWW using the Chi-Alg complex could be used in feed formulations. They could be used for food production in countries where regulatory agencies allow the use of chitosan in the production of food ingredients.

Maternal dietary conjugated linoleic acid alters hepatic triacylglycerol and tissue fatty acids in hatched chicks.

The effects of feeding CLA to hens on newly hatched chick hepatic and carcass lipid content, liver TAG accumulation, and FA incorporation in chick tissues such as liver, heart, brain, and adipose were studied. These tissues were selected owing to their respective roles in lipid assimilation (liver), as a major oxidation site (heart), as a site enriched with long-chain polyunsaturates for function (brain), and as a storage depot (adipose). Eggs with no, low, or high levels of CLA were produced by feeding hens a corn-soybean meal-basal diet containing 3% (w/w) corn oil (Control), 2.5% corn oil + 0.5% CLA oil (CLA1), or 2% corn oil + 1.0% CLA oil (CLA2). The egg yolk content of total CLA was 0.0, 1.0, and 2.6% for Control, CLA1, and CLA2, respectively (P< 0.05). Maternal dietary CLA resulted in a decrease in chick carcass total fat (P < 0.05). Liver tissue of CLA2 chicks had the lowest fat content (P < 0.05). The liver TAG content was 8.2, 5.8, and 5.1 mg/g for Control, CLA1, and CLA2 chicks, respectively(P < 0.05). The chicks hatched from CLA1 and CLA2 incorporated higher levels of cis-9,trans-11 CLA in the liver, plasma, adipose, and brain than Control (P< 0.05). The content of 18:0 was higher in the liver, plasma, adipose, and brain of CLA1 and CLA2 than Control (P< 0.05), but no difference was observed in the 18:0 content of heart tissue. A significant reduction in 18:1 was observed in the liver, plasma, adipose, heart, and brain of CLA1 and CLA2 chicks (P< 0.05). DHA (22:6n-3) was reduced in the heart and brain of CLA1 and CLA2 chicks (P < 0.05). No difference was observed in carcass weight, dry matter, or ash content of chicks (P> 0.05). The hatchabilities of fertile eggs were 78, 34, and 38% for Control, CLA1, and CLA2, respectively (P< 0.05). The early dead chicks were higher in CLA1 and CLA2 than Control (18 and 32% compared with 9% for Control), and alive but not hatched chicks were 15 and 19% for CLAl and CLA2, compared with 8% for Control (P < 0.05). Maternal supplementation with CLA leads to a reduction in hatchability, liver TAG, and carcass total fat in newly hatched chicks.

Hepatic lipid characteristics and histopathology of laying hens fed CLA or n-3 fatty acids.

The effect of dietary CLA and n-3 PUFA on hepatic TAG accumulation, histopathology, and FA incorporation in lipid classes by laying chickens was investigated. One hundred twenty 30-wk-old single comb white leghorn laying hens were distributed randomly to four treatments (3 replications of 10 birds) and were fed diets containing CLA and animal fat (Diet I), 18:3n-3 (Diet II), or long-chain n-3 FA (Diet III). A sunflower oil (n-6 FA)-based diet vvas the control. Feeding Diet I resulted in an increase in hepatic total lipids (P < 0.05). The liver TAG content was 32.2, 18.9, 29.4, and 18.7 mg/g for hens fed Diet I, Diet II, Diet III, and the control diet, respectively (P< 0.05). The serum TAG was lowest in birds fed Diet II (P < 0.05). Diet I resulted in an increase in the total number of fat vacuoles and lipid infiltration in hepatocytes (P < 0.05). The number of cells with 75% or higher lipid vacuolation was observed only in birds fed Diet I. Feeding diets containing CLA resulted in an increase in the content of the c9,t11 CLA isomer in liver TAG and PC (P < 0.05). No difference was observed in the CLA concentration of hepatic PE fractions. The content of DHA (22:6n-3) was higher in the TAG, PC, and PE of hens fed Diet II and Diet III than Diet I and the control (P < 0.05). Feeding CLA resulted in an increase in total saturated FA in the TAG and PC fractions (P < 0.05). Long-term feeding of CLA in laying birds leads to an increase in liver TAG and may predispose birds to fatty liver hemorrhagic syndrome.

Dietary CLA alters yolk and tissue FA composition and hepatic histopathology of laying hens.

The effect of dietary CLA along with n-3 PUFA on yolk FA profile and hepatic lipid accumulation was investigated. Laying hens (n = 40) were randomly assigned to four experimental diets containing 0, 0.5, 1.0, or 2.0% CLA. Menhaden oil was used as the source of n-3 PUFA. Dietary CLA did not affect the total lipid content of egg yolk (P > 0.05). The amounts of CLA isomers (cis-9 trans-11, trans-10 cis-12) in the egg yolk were proportional to the levels of CLA in the diet (P < 0.05). The total CLA content in the egg yolk was 0, 0.97, 2.4, and 5.3 wt%, respectively (P < 0.05). Addition of CLA resulted in an increase in saturated FA (P < 0.05) with a concomitant reduction in monounsaturated FA (P < 0.05) in the yolk, liver, abdominal fat, breast, and thigh muscle. No difference in saturated and monounsaturated FA content in heart and spleen tissue was noted. Dietary CLA at all concentrations resulted in an increase (P < 0.05) in the total number of fat vacuoles and lipid infiltration in hepatocytes. The number of cells with 75% or higher lipid vacuolation in the cytoplasm was also increased (P < 0.05) by 2.0% CLA. Dietary CLA at 0.5% levels resulted in an increase (P < 0.05) in the total lipid content of hepatic tissue. The total lipid content in leg muscle was lower (P < 0.05) in CLA-fed birds. However, no effect of CLA on lipid content of breast muscle, heart, spleen and adipose tissue was observed (P > 0.05). The current study used CLA in a FFA form. The effects of using CLA in other form such as TG on avian hepatic tissue need to be investigated.