Dietary biotin effects on polyunsaturated fatty acids in chick tissue lipids and prostaglandin E2 levels in freeze-clamped hearts

Nutritional requirements of meat-type and egg-type ducks: what do we know?

The demand for duck meat, duck eggs, and associated products is increasing each year. Classic and modern selection programs have been applied to enhance the economic traits of ducks to satisfy the requirements of consumers and enhance the incomes of producers. The nutritional requirements of unselected ducks may not be adequate, however, to fulfill the potential productivity performance of modern birds, including both meat-type and egg-type ducks. In particular, an imbalanced diet is associated with low productive performance and signs of nutritional deficiency (if insufficient nutrients are supplied), as well as with high feed costs and manure problems that reflect flock health and welfare (if excessive nutrients are supplied). Thus, the main aim of this review is to summarize the results of previous studies that estimated the nutrient requirements of meat-type and egg-type ducks in order to evaluate current knowledge and to identify further issues that need to be addressed. In addition, the results obtained in previous studies are compared in order to understand how to lower commercial feed costs, fulfill the genetic potential of selected ducks, protect the environment from pollution, and satisfy the welfare and health needs of ducks.

Biotin biochemistry and human requirements

Human biotin turnover and requirements can be estimated on the basis of (1) concentrations of biotin and metabolites in body fluids, (2) activities of biotin-dependent carboxylases, and (3) the urinary excretion of organic acids that are formed at increased rates if carboxylase activities are reduced. Recent studies suggest that the urinary excretions of biotin and its metabolite bisnorbiotin, activities of propionyl-CoA carboxylase and beta-methylcrotonyl-CoA carboxylase in lymphocytes, and urinary excretion of 3-hydroxyisovaleric acid are good indicators of marginal biotin deficiency. On the basis of studies using these indicators of biotin deficiency, an adequate intake of 30 microg (123 nmoles) of biotin per day is currently recommended for adults. The dietary biotin intake in Western populations has been estimated to be 35 to 70 microg/d (143-287 nmol/d). Recent studies suggest that humans absorb biotin nearly completely. Conditions that may increase biotin requirements in humans include pregnancy, lactation, and therapy with anticonvulsants or lipoic acid.

Interactions and antigen dependence of dietary n-3 and n-6 polyunsaturated fatty acids on antibody responsiveness in growing layer hens

Effects of four levels of dietary linoleic acid (LA), an n-6 fatty acid, and four levels of alpha-linolenic acid (LNA), an n-3 fatty acid, and their interactions on immune responses in growing layer hens were studied. Immune responses were induced by injection with keyhole limpet hemocyanin (KLH) or Mycobacterium butyricum particles at 35 d of age. Antibody (Ab) responses were measured until 21 d after immunization. In addition, delayed-type hypersensitivity, lymphocyte proliferation, weekly feed intake, and BW gain were studied. At Day 7 after immunization, anti-M. butyricum titers in the M. butyricum-immunized hens were decreased by the increase of dietary LA (P < 0.05). In the period from 10 to 14 d after immunization, anti-KLH Ab titers in KLH-immunized animals were affected by the interaction of dietary LA with LNA (P < 0.01). High dietary levels of LA or LNA increased the anti-KLH Ab response. However, at high levels of dietary LA and LNA, anti-KLH Ab titers were not increased. In the same period, anti-M. butyricum Ab titers of M. butyricum-immunized hens were affected by the interaction of dietary LA with LNA (P < 0.05). At low levels of LA and LNA, increased LA levels decreased the Ab response, whereas increased LNA levels at low LA levels hardly affected the anti-M. butyricum response. At a high level of LA, increased dietary LNA increased the anti-M. butyricum response. In vitro proliferation of peripheral blood leukocytes after stimulation with concanavalin A (ConA) was higher in chickens with a high level of dietary LNA. Feed intake decreased when the dietary levels of LA or LNA increased. However, BW gain was not affected by dietary treatments. Feed conversion was more efficient in birds fed high levels of LA and LNA. The present study indicates that various factors affect the Ab responses. First, the interaction of n-6 and n-3 polyunsaturated fatty acids (PUFA) is more important than the separate effects of n-3 or n-6. Second, the actions of dietary PUFA were different between antigens of a different nature. Third was the nature of the antigen affects when dietary PUFA exert their actions and the persistence of these effects. The presence of these multiple factors affecting immune responses should be considered when comparing effects of dietary PUFA on immune responses.

Calcium metabolism, osteoporosis and essential fatty acids: a review

Essential fatty acid (EFA)-deficient animals develop severe osteoporosis coupled with increased renal and arterial calcification. This picture is similar to that seen in osteoporosis in the elderly, where the loss of bone calcium is associated with ectopic calcification of other tissues, particularly the arteries and the kidneys. Recent mortality studies indicate that the ectopic calcification may be considerably more dangerous than the osteoporosis itself, since the great majority of excess deaths in women with osteoporosis are vascular and unrelated to fractures or other bone abnormalities. EFAs have now been shown to increase calcium absorption from the gut, in part by enhancing the effects of vitamin D, to reduce urinary excretion of calcium, to increase calcium deposition in bone and improve bone strength and to enhance the synthesis of bone collagen. These desirable actions are associated with reduced ectopic calcification. The interaction between EFA and calcium metabolism deserves further investigation since it may offer novel approaches to osteoporosis and also to the ectopic calcification associated with osteoporosis which seems to be responsible for so many deaths.

Dietary (n-3) and (n-6) polyunsaturates and acetylsalicylic acid alter ex vivo PGE2 biosynthesis, tissue IGF-I levels, and bone morphometry in chicks

This study examined the effects of dietary (n-6) and (n-3) polyunsaturated fatty acids (PUFA) and acetylsalicylic acid (ASA) on bone ash content, morphometry, fatty acid composition, ex vivo PGE2 biosynthesis, tissue IGF-I concentration, and serum alkaline phosphatase (ALPase) activity in chicks. Newly hatched chicks were fed a semipurified diet containing soybean oil (S) or menhaden oil / safflower oil (M) at 90 g/kg. At 4 days of age, chicks were divided into four equal treatment groups receiving 0 mg [symbol: see text] or 500 mg [symbol: see text] of ASA/kg of diet: S[symbol: see text]ASA, M[symbol: see text]ASA, S[symbol: see text]ASA, and M[symbol: see text]ASA. Lipid and ASA treatments did not affect bone length, bone ash, or bone mineral content in chicks. Chicks fed M had increased fractional labeled trabecular surface and tissue level bone formation rates, independent of ASA treatment, compared with those given S. A significant fat x ASA interaction effect was found for trabecular bone volume, thickness, separation, and number. Chicks fed S had higher 20:4(n-6) but lower 20:5(n-3) concentrations in liver and bone compared with those given M. Ex vivo PGE2 biosynthesis was higher in liver homogenates and bone organ cultures of chicks fed S compared with the values for those given M at 17 days. ASA treatment decreased ex vivo PGE2 production in liver homogenates and bone organ cultures of chicks, independent of the dietary lipids. Chicks fed ASA had a lower concentration of IGF-I in tibiotarsal bone compared with those not given ASA at 19 days. Serum ALPase activity was higher in chicks given M compared with those fed S, but the values were reversed with ASA feeding. This study demonstrated that both dietary fat and ASA modulated bone PGE2 biosynthesis, and that (n-3) PUFA and fat x ASA interactions altered bone morphometry.

Response of layer breeders to dietary acetylsalicylic acid. 2. Effects on circulating concentrations of prostaglandin F2 alpha

White Leghorn breeder hens were fed 0, .05, or .40% acetylsalicylic acid (ASA) for either 1 wk or 1 mo. Blood samples were collected 4 h postentrance of an egg into the uterus (baseline) and at oviposition of a hardshelled (HS) egg. Plasma samples were analyzed for prostaglandin (PG) F2 alpha by radioimmunoassay. Peripheral PGF2 alpha concentrations peaked upon oviposition of a HS egg in both ASA-fed hens as well as the controls (0% ASA). The levels of dietary ASA and the duration of time the ASA was administered did not affect baseline or peak PGF2 alpha concentrations. It was concluded that either the timing or route of administration of ASA resulted in the failure of ASA to effectively reduce peak peripheral PGF2 alpha concentrations.

Hydrogenated oil decreases tissue concentrations of n-6 polyunsaturated fatty acids and may contribute to dyschondroplasia in broilers

1. In a factorial design of dietary treatments, male Ross broilers were given diets containing soyabean oil, hydrogenated soyabean oil (as a source of trans-fatty acids) or feed fat with either 0 or 300 micrograms of added D-biotin/kg. 2. Growth to 28 d was not influenced by the dietary treatments. 3. Length of tibiotarsal bones was reduced (P less than 0.05) and severity of leg bone cartilage lesions, characteristic of dyschondroplasia, was highest (P less than 0.05) in broilers fed on diets containing hydrogenated soyabean oil. 4. Feeding hydrogenated soyabean oil lowered (P less than 0.05) the concentrations of C20:4n6 and the ratios of C20:4n6/C18:2n6 in liver and growth plate cartilage. 5. Growth plate cartilage from birds affected with dyschondroplasia contained lower proportions of prostaglandin precursor fatty acids compared with normal growth plate. 6. It is speculated that an inhibition of prostaglandin biosynthesis brought about by the presence of trans-fatty acids might contribute to the occurrence of lesions similar to dyschondroplasia.

Eicosanoic fatty acid reduction in the tibiotarsus of biotin-deficient chicks

Day-old male broiler chicks (Hubbard x Hubbard) were fed a purified diet containing biotin at 0 microgram/kg of diet (biotin-deficient) or 500 micrograms/kg of diet (biotin-adequate). Biotin-deficient (BD) chicks had decreased growth and feed efficiency and greater twisted leg and dermatitis symptoms than biotin-adequate (BA) chicks. Lipids in cortical bone of the tibiotarsi in BD chicks contained higher levels of linoleate, gamma-linolenate, and alpha-linolenate. Prostaglandin precursors, dihomo-gamma-linolenate (20:3 omega 6), arachidonate (20:4 omega 6), and eicosapentaenoate (20:5 omega 3) were all lower in BD chicks compared with BA chicks. Periosteal bone appositional and bone formation rates, and percent new bone formation were reduced in the tibiotarsi of BD chicks. Anatomically there were two different bone modeling patters at the mid-diaphysis. The cortex was thickest laterally in chicks fed the BA diet and thickest medially in chicks fed the BD diet. The quantitative differences in bone growth and the distinct bone modeling patterns, coupled with corresponding decreases in PG precursors, suggest that biotin deficiency may alter bone growth and modeling via a PG-dependent mechanism.

Levels of dihomo-gamma-linolenate are depressed in heart phosphatidylcholine and phosphatidylethanolamine in the biotin-deficient chick

Male broiler chicks were fed a purified diet with 0 or 500 micrograms/kg of added biotin for 21 days posthatch. Fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were determined in erythrocytes and in heart mitochondria and microsomes of chicks at 12 and 21 days of age. The biotin-deficient (BD, 0 microgram biotin) chicks had lower body weights, lower feed efficiencies, and higher scores for dermatitis and twisted leg than the biotin-adequate (BA, 500 micrograms biotin) chicks. The erythrocyte arachidonate level in PC was higher in BD chicks compared to the BA controls, and the level increased with age in PC and PE in the erythrocytes. The level of dihomo-gamma-linolenate (20:3 omega 6) in PC and PE in heart mitochondria and microsomes was consistently decreased in BD chicks compared with that in BA chicks. In heart subcellular organelles, the level of arachidonate in PC increased, but the level of dihomo-gamma-linolenate in PE decreased with age. These data demonstrate that biotin deficiency results in dramatic changes in the fatty acid composition of specific phospholipids in chick erythrocytes and heart subcellular organelles.

Influences of biotin deficiency and dietary trans-fatty acids on tissue lipids in chickens

1. The combined effects of feeding hydrogenated fats and varying the levels of biotin and linoleate (18:2 omega 6) on polyunsaturated fatty acids were studied in the chicken. 2. Biotin deficiency signs were not exacerbated by feeding hydrogenated fats or by diets low in linoleate for 21 d. 3. Biotin deficiency resulted in proportionately higher levels of 18:2 omega 6 and gamma-linolenate (18:3 omega 6) in liver triglycerides, and lower levels of dihomo-gamma-linolenate (20:3 omega 6) in liver and heart phospholipids irrespective of the 18:2 omega 6 level in the diet. 4. Biotin deficiency did not alter arachidonate (20:4 omega 6) levels in tissue lipids at 21 d. 5. Feeding high levels of trans-18:1 isomers with adequate biotin led to reduced 20:3 omega 6 and 20:4 omega 6 levels in liver and heart phospholipids with compensatory increases in omega 3 fatty acids. 6. The trans-isomers of 18:1 were incorporated into several tissues of the chick. Incorporation was dependent on the levels fed. Very small amounts were incorporated into brain compared with other tissues when dietary trans-isomer levels were high, but were similar when dietary trans-isomer levels were low. The trans-18:1 isomers appear to be preferentially incorporated into phospholipids as opposed to triglycerides in heart and liver.