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

The hidden function of egg white antimicrobials: egg weight-dependent effects of avidin on avian embryo survival and hatchling phenotype

Avidin is a key egg white antimicrobial protein with strong binding capacity for biotin, an essential growth and immune cell precursor. As such, it is assumed to have a pronounced, though still poorly explored, effect on hatchling phenotype. We tested the effect of experimentally increased egg white avidin concentration (AVIDIN+) on hatching success, chick morphology, post-hatching growth performance and innate immune function in a model bird, Japanese quail (Coturnix japonica). Probability of embryo survival in the late embryonic phase increased with increasing egg weight in control eggs, but not in AVIDIN+ eggs. Chicks hatching from lighter AVIDIN+ eggs had a shorter tarsus than chicks hatching from heavier AVIDIN+ eggs. This suggests that an increase in egg white avidin favours embryo survival in lighter eggs during late embryogenesis, but at the expense of reduced structural body size. Plasma complement activity in 6-day-old AVIDIN+ chicks decreased with increasing body mass and tarsus length; the opposite was observed in control chicks, implying that the later post-hatching innate immune function of larger chicks was compromised by an increase in egg white avidin concentration. Here, we document an important role of egg white antimicrobials in maintenance of embryo viability, avian hatchling morphology and immune phenotype.

Summary: This is the first experimental study to evaluate the effects of increased concentration of egg white antimicrobial protein avidin on embryo viability, hatchling morphology and immune phenotype in birds.

EFA supplementation in children with inattention, hyperactivity, and other disruptive behaviors

This pilot study evaluated the effects of supplementation with PUFA on blood FA composition and behavior in children with Attention-Deficit/Hyperactivity Disorder (AD/HD)-like symptoms also reporting thirst and skin problems. Fifty children were randomized to treatment groups receiving either a PUFA supplement providing a daily dose of 480 mg DHA, 80 mg EPA, 40 mg arachidonic acid (AA), 96 mg GLA, and 24 mg alpha-tocopheryl acetate, or an olive oil placebo for 4 mon of double-blind parallel treatment. Supplementation with the PUFA led to a substantial increase in the proportions of EPA, DHA, and alpha-tocopherol in the plasma phospholipids and red blood cell (RBC) total lipids, but an increase was noted in the plasma phospholipid proportions of 18:3n-3 with olive oil as well. Significant improvements in multiple outcomes (as rated by parents) were noted in both groups, but a clear benefit from PUFA supplementation for all behaviors characteristic of AD/HD was not observed. For most outcomes, improvement of the PUFA group was consistently nominally better than that of the olive oil group; but the treatment difference was significant, by secondary intent-to-treat analysis, on only 2 out of 16 outcome measures: conduct problems rated by parents (-42.7 vs. -9.9%, n = 47, P = 0.05), and attention symptoms rated by teachers (-14.8 vs. +3.4%, n = 47, P = 0.03). PUFA supplementation led to a greater number of participants showing improvement in oppositional defiant behavior from a clinical to a nonclinical range compared with olive oil supplementation (8 out of 12 vs. 3 out of 11, n = 33, P = 0.02). Also, significant correlations were observed when comparing the magnitude of change between increasing proportions of EPA in the RBC and decreasing disruptive behavior as assessed by the Abbreviated Symptom Questionnaire (ASQ) for parents (r = -0.38, n = 31, P < 0.05), and for EPA and DHA in the RBC and the teachers' Disruptive Behavior Disorders (DBD) Rating Scale for Attention (r = -0.49, n = 24, P < 0.05). Interestingly, significant correlations were observed between the magnitude of increase in alpha-tocopherol concentrations in the RBC and a decrease in scores for all four subscales of the teachers' DBD (Hyperactivity, r = -0.45; Attention, r= -0.60; Conduct, r = -0.41; Oppositional/Defiant Disorder, r = -0.54; n = 24, P < 0.05) as well as the ASQ for teachers (r = -0.51, n = 24, P < 0.05). Thus, the results of this pilot study suggest the need for further research with both n-3 FA and vitamin E in children with behavioral disorders.

Analytical techniques for determining biotin

Biotin is a vitamin of the B-complex, which plays an important biochemical role in every living cell. In the recent years, the interest in this vitamin has been rekindled, mainly due to its association with serious human disorders, such as the inherited syndrome multiple carboxylase deficiency, which can be successfully treated with biotin administration. Diagnosis of biotin deficiency as well as monitoring of biotin levels in biological fluids of patients receiving biotin treatment is crucial. Equally important is the determination of biotin levels in pharmaceutical preparations as well as in food and food supplement products, which constitute the main source of biotin in humans. Several analytical methods for measuring biotin in various samples, e.g. human fluids, pharmaceutical formulations, food material etc., have been reported in the literature. In this review, the most representative of these methods are presented, and their characteristics are evaluated.

Optimum nutrition: thiamin, biotin and pantothenate

The metabolism of glucose is deranged in thiamin deficiency, but once any deficiency has been corrected there is no further effect of increased thiamin intake on the ability to metabolize glucose through either pyruvate dehydrogenase (EC 1.2.4.1) and the citric acid cycle, or the pentose phosphate pathway, in which transketolase (EC 2.2.1.1) is the thiamin-dependent step. It has been suggested that the Wernicke-Korsakoff syndrome is associated with a genetic variant of transketolase which requires a higher than normal concentration of thiamin diphosphate for activity. This finding would suggest that there may be a group of the population who have a higher than average requirement for thiamin, but the evidence is not convincing. There are no estimates of biotin requirements, but either coenzyme saturation of erythrocyte pyruvate carboxylase, or the excretion of 3-hydroxy-isovalerate (perhaps after a test dose of leucine) could be used to assess requirements in depletion-repletion studies. Biotin deficiency leads to impaired glucose tolerance, but it is unlikely that glucose tolerance could be used to assess optimum biotin status, since other more common factors affect glucose tolerance to a greater extent. Plasma triacylglycerol and nonesterified fatty acids are moderately elevated in pantothenic acid deficiency. However, this is unlikely to be useful in assessing pantothenate status, since again, other more common factors affect plasma lipids. To date there are no biochemical indices of adequate pantothenate nutrition, and no estimates of requirements.

Influence of heated and nonheated partially hydrogenated dietary fats on ileal chyme fat and fatty acid composition of ileal mucosa in pigs

In this study the effects of partially hydrogenated chemically processed fats (CPF) and non-CPF on the ileal chyme fat and the fatty acid (FA) profile of the ileal mucosa and the subcutaneous tissue were analyzed. Samples were collected via an ileocutaneous fistula. For three months pigs were fed a control meal or diets containing either non-CPF high on 16:0, non-CPF high on 18:2 n6, CPF with 50% trans-18:1 or 20% trans-18:1. The latter fat was used after heat treatment. With both CPF diets, the fat content in the ileal chyme was three times higher than with non-CPF. In contrast to subcutaneous tissue reflecting dietary composition, changes in FA profile of ileal mucosa were restricted. Each non-CPF resulted in an increase of the characteristic major dietary FA. Both CPF increased the mucosal trans-FA percentage from 0 to 12% on average, although dietary composition was different. This study suggests: (1) less effects of trans-FA on the regulation of intraluminal fat load compared to saturated and cis-polyunsaturated FA, and (2) higher mucosal incorporation of trans-FA with heated CPF. This may play a role in the development of epithelial lesions in the ileum, which are known following ingestion of these fats.

Dietary lipids modify the fatty acid composition of cartilage, isolated chondrocytes and matrix vesicles

The effects of dietary lipids on the fatty acid composition of hyaline cartilage, epiphyseal chondrocytes (EC) and matrix vesicles (MV) were evaluated in chicks. A basal semipurified diet was fed to chicks containing one of the following lipid sources at 70 g/kg: soybean oil, butter+corn oil, margarine+corn oil or menhaden oil+corn oil (MEC). Articular and epiphyseal growth cartilage were isolated from the proximal tibiotarsus; EC and MV were subsequently released by trypsin (EC 3.4.21.4) and collagenase (EC 3.4.24.3) digestion followed by ultracentrifugation. The fatty acid composition of polar lipids in chick epiphyseal cartilage at three and six weeks, as well as articular cartilage, EC and MV at eight weeks of age revealed the presence of high levels of saturated and monounsaturated fatty acids (up to 85.5%) but low levels of n-6 polyunsaturated fatty acids (PUFA) (2.6-10.2%). Mead acid (20:3n-9, > 3%) was also present in cartilage, EC and MV lipids, and was unaffected by the dietary lipid treatments. Total n-3 PUFA concentrations were the highest in cartilage, EC and MV of chicks consuming MEC. Feeding MEC lowered the levels of 20:4n-6 in cartilage, but increased 20:5n-3 levels. The data are consistent with those reported previously which showed that cartilage tissues are low in n-6 PUFA and that they contain 20:3n-9. We furthermore demonstrated that the PUFA composition of cartilage can be modified by dietary lipids.

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.

Influence of dietary flaxseed oil on the performance, muscle protein deposition, and fatty acid composition of broiler chicks

Experiments were conducted to assess the effect of feeding flaxseed oil on the performance, muscle protein deposition, and fatty acid composition of broiler chicks. Four levels of dietary flaxseed oil were fed in combination with animal tallow to give a total of 6% added fat in the diets. The diets were isonitrogenous and isocaloric. Mortality, weight gain, feed consumption, and feed efficiency were not significantly different among treatments. Dietary treatments had no significant effects on the relative weights of the Extensor digitorum communis and Sartorius muscles nor on their protein or lipid contents. Feeding flaxseed oil resulted in increased accumulation of omega 3 fatty acids in skeletal muscle lipids. Increased amounts of desaturation and elongation products (C20:3, C20:5, C22:5, and C22:6) of alpha-linolenate (C18:3 omega 3) were observed in the Sartorius muscle lipids of chicks fed flaxseed oil. Amounts of these omega 3 fatty acids increased with duration of feeding. The amounts of omega 6 fatty acids (C20:2, C20:3, C20:4) were significantly depressed in muscle lipids after 21 days of feeding flaxseed oil. The effects of flaxseed oil on tissue amounts of individual saturated fatty acids were minimal, but amounts of monounsaturated fatty acids, especially C18:1, were depressed.