Serum aminotransferase activities and plasma free amino acid concentration as criteria for pyridoxine nutritional status of chicks

Vitamin B6 in the etiology of gizzard erosion in growing chickens

Six experiments have been completed on day-old male cross-bred chicks for periods of up to 2 and 4 weeks to learn more about the role of pyridoxine in the etiology of gizzard erosion. At the end of each experiment, chicks were sacrificed and their gizzards removed and scored for the severity and incidence of erosion. The results of these experiments confirm the previous finding that the severity and incidence of gizzard erosion is increased by B6 deficiency. They further show that taurocholic acid, at 1% of the diet, had a protective effect against this erosion. Feeding B6-adequate rations to chicks that previously had been fed a B6-deficient diet led to partial healing of gizzard erosions. Results also indicate that the feeding of purified diets to growing chickens produces a higher incidence of erosion than that of practical-type diets. Texture of the diet did nt influence the incidence of the erosion, because grinding a practical diet to the same fineness as a purified diet did not increase gizzard erosion. Pair-feeding experiments showed that gizzard erosion in partially starved chicks was not a specific result of anorexia but of deficiencies in certain nutrients, one of which is vitamin B6.

Interrelationship between dietary pyridoxine and free plasma amino acids in chicks

The interrelationships between dietary pyridoxine and free plasma amino acids in young chicks were studied with two different diets. Chicks fed isolated soybean protein supplemented with less than 1.0 mg pyridoxine-HCl/kg diet had reduced body weight gain and feed consumption and a higher mortality rate (19%) than those fed 1 or 5 mg pyridoxine-HCl/kg. A casein diet required greater supplementation (2.0 mg pyridoxine/kg) to prevent reduced body weight gain and depressed feed intake. The concentrations of free plasma taurine, threonine, and serine were significantly lower in chicks fed the isolated soybean protein diet supplemented with less than 1.0 mg pyridoxine-HCl/kg, while those of isoleucine, valine, glycine, and ornithine were significantly higher than in chicks fed greater levels of pyridoxine. Supplementation of casein diets with less than 2.0 mg resulted in a significant accumulation of threonine, glycine, cystathionine, and ornithine. Valine was significant higher in chicks fed casein supplemented with only .6 mg pyridoxine-HCl/kg. Feeding isolated soybean protein or casein diets without any pyridoxine supplementation resulted in the dealth of 95% and 100% of the chicks, respectively. Pair feeding a group fed the isolated soybean protein diet supplemented with 1.0 mg to a group receiving .5 mg pyridoxine-HCl/kg resulted in a similar body weight gain and concentration of amino acids in the plasma.

Studies on the nutrition of marine flatfish. The pyridoxine requirement of turbot (Scophthalmus maximus)

1. Diets containing graded levels of pyridoxine hydrochloride (to supply 0.26--30 mg pyridoxine/kg) were given to seven duplicate groups of turbot (Scophthalmus maximus) for 12 weeks and their growth rate was measured during this period. 2. Good growth was obtained on all treatments except those groups given less than 1.0 mg pyridoxine/kg diet. These fish grew normally until weeks 8--10 but thereafter their weight gain was significantly less than that for other treatments. 3. Measurements of aspartate aminotransferase (EC 2.6.1.1) in muscle and liver and of alanine amino-transferase (EC 2.6.1.2) in liver of the turbot showed that the activities of these enzymes increased with increasing dietary pyridoxine intake up to a level of 2.5 mg pyridoxine/kg. The activities of these enzymes were not further enhanced by additional dietary pyridoxine. 4. Percentage stimulation of these enzymes by pre-incubation of extracts with pyridoxal phosphate was minimal with those groups of turbot given 2.5 mg pyridoxine/kg diet or more. 5. It is concluded that the dietary requirement of turbot for vitamin B6 can be safely met with a diet containing between 1.0 and 2.5 mg pyridoxine/kg. 6. An eighth group of turbot given the pyridoxine antagonist 4-deoxypyridoxine hydrochloride (20 mg/kg) showed retarded growth after 2 weeks, together with a high mortality rate.

Effects of magnesium and high dietary intakes of pyridoxine on the chick

Day-old broiler-type male chicks were used to determine what effects magnesium and high dietary pyridoxine had on the chick's performance. The chicks were randomly assigned to 15 treatments of magnesium at 875, 1375 and 1875 mg/kg. diet and pyridoxine at 1, 4, 31, 301, and 3001 mg/kg. diet in a 3 x 5 factorial block design. A regression was used to study some of the criteria. The highest mortality of 20% occurred in chicks on the 1875 mg. magnesium-3001 mg. pyridoxine treatment. Magnesium and pyridoxine had highly significant effects on body moisture. Effects due to magnesium and pyridoxine and the interaction between the two were highly significant for weight gain and the efficiency of feed utilization (E.F.U.) At 1875 mg. magnesium/kg diet, maximum growth response and E.F.U. were predicted to occur on 10 and 39 mg pyridoxine/kg diet, respectively, Neither magnesium nor the interaction between magnesium and pyridoxine had any significant effect on carcass protein. Pyridoxine had a highly significant effect on carcass protein. Maximum response in carcass protein occurred at 31 mg. pyridoxine/kg diet irrespective of magnesium level. Serum aminotransferase activity (S.A) was significant for magnesium, pyridoxine and the interaction between the two. Pyridoxine requirement for maximum S.A. was 49 mg/kg diet at 1875 mg magnesium/kg diet. Pyridoxine requirement for maximum response was highest for S.A. and least for growth. But S.A. had the highest R2 whereas growth had the least.