Chick Bioassay Research Articles

The Antirachitic Activity of Solanum glaucophyllum Leaves

Solanum glaucophyllum leaves, collected from stands growing in tropical and subtropical areas, have been assayed for their antirachitic activity. The equivalent to 24 - 120 micrograms of cholecalciferol per gram of dry leaves has been measured the rachitic chick bioassay. Leaf activity appears to be influenced by geographical location or climatic conditions and by the development of the plant (it is higher in vegetative than in reproductive state).

Utilization of the D- and L-Isomers of Methionine and Methionine Hydroxy Analogue as Determined by Chick Bioassay

Young chicks were fed sulfur-amino acid (SAA) deficient soy protein or crystalline amino acid diets to evaluate the relative efficacy of the D- and L-isomers of methionine and 2-hydroxy-4-(methylthiobutyrate)Ca (OH-methionine). With crystalline amino acid diets, D-OH-methionine ([alpha] D25 = +24.3) was decisively superior to L-OH-methionine ([alpha] D25 = -25.3) as a source of methionine activity. The D-isomer of OH-methionine was also much more toxic than the L-isomer as measured by magnitude of growth depression and severity of hemolytic anemia. DL-OH-methionine was intermediate in toxicity between the pure D- and L-isomers, but its efficacy for growth promotion was greater than what would have been predicted from its (equal) content of the two isomers. With methionine, the L-isomer was superior in growth-promoting efficacy to the D-isomer; DL-methionine, however, more nearly paralleled the response to L- than to D-methionine. In all cases where the crystalline amino acid diet was fed, regardless of isomeric form, methionine was vastly superior to OH-methionine as a source of SAA activity. With the soy-protein diet, on the other hand, differences in efficacy between methionine and OH-methionine were minimal, and isomeric form was of lesser consequence.

Evaluation of protein quality of poultry feedingstuffs. 1. Comparison of chick bioassays

SummaryBody-weight gain, protein efficiency ratio (PER), standardized protein efficiency ratio (Std PER) and gross protein value (GPV, GPV1and GPV2) bioassays were compared with nitrogen incorporation efficiency (NTE) for their accuracy and precision to determine protein quality of fish meal (FM), groundnut cake (GN), mustard cake (MS) and cottonseed cake (CS) for poultry. Results showed that all the bioassays were significantly (P < 0·05) correlated with NIE and were equally effective in ranking the samples of FM, GN, MS and CS according to their protein quality although body-weight gain procedure was less sensitive.

RADIOMETRIC DETERMINATION AND CHICK BIOASSAY OF FOLACIN IN FORTIFIED AND UNFORTIFIED FROZEN FOODS

ABSTRACTA radiometric assay for food folacin based on the competitive protein binding procedure was developed. The method is rapid, reliable and comparable to the microbiological assay. Cooking and storage did not significantly affect the folacin content of frozen fortified or unfortified frozen dinners and pies. Food folacin availability was measured by chick bioassay. The procedure involves feeding semi‐purified diets containing various levels of folic acid and/or cooked or uncooked frozen convenience foods and measuring plasma and RBC folacin. Levels were directly related to folic acid intake from semipurified diets. Availability of folacin acid added to TV dinners and pies was demonstrated by elevation of plasma and RBC folacin, but fortification of vegetables did not cause consistent elevation.

Serum Somatomedin A in Chronic Renal Failure*

The serum levels of somatomedin A, determined by radioreceptor assay, were significantly higher in 57 adult patients with chronic renal failure (X = 2.57 +/- 0.12 U/ml) than in healthy subjects (n = 131; X = 0.77 +/- 0.02 U/ml). A positive correlation was found between somatomedin A and creatinine levels (r = 0.33), but somatomedin A levels did not decrease after hemodialysis. A reduction was only observed after successful renal allografting. Immunoreactive somatomedin A was also found to be increased in patients with chronic renal failure (X = 2.61 +/- 0.21 U/ml), whereas low levels were obtained by the chick bioassay. However, after separating the inhibitory factors from the stimulatory factors by gel chromatography at neutral pH, uremic serum was shown to contain increased levels of somatomedin activity. Although all somatomedin A, determined by different techniques, was present in high molecular forms, the elution pattern differed from that seen in patients with acromegaly.

Analysis of Fat-Soluble Vitamins. XVII. Comparison of Chemical and Biological Assays of Vitamin D

Abstract Two methods, the chemical assay using maleic anhydride addition and the British Standard Institution chick bioassay, were used to analyze samples from vitamin D3 resin batches manufactured over a period of about 4 years. Statistical analysis of data obtained for vitamin D shows that (1) the reproducibility of the chemical assay has a coefficient of variation of 0.7% ; (2) the chemical assay is suitable for controlling the dilution procedure of resins in oil, the product variability being represented by a coefficient of variation of 1.7% ; (3) the agreement between the average values obtained by the bioassay and the chemical method is satisfactory (geometric mean ratio = 99.7%, n = 39); (4) the chick bioassay has 95% limits of variation of about ±30% for single results.

An improved method for the microbiological assay of available amino acids in proteins using Tetrahymena pyriformis

1. A standard microbiological procedure for the assay of available amino acids in proteins using Tetrahymena pyriformis has been modified by evaluating cell growth from the tetrahymanol content of the cultures by gas-liquid chromatography (GLC). 2. This modification improves the precision of the method compared with cell-counting techniques and provided automatic injection facilities are available for the GLC, the procedure is not excessively time-consuming. 3. It has been confirmed that enzymic predigestion is essential for all except the most soluble proteins and a satisfactory method using pronase has been incorporated into the microbiological procedure. 4. After enzymic digestion of the sample, growth of Tetrahymena with many proteins can be measured turbidimetrically, but particulate matter still persists with a proportion of samples, particularly those of plant origin, and the GLC method is therefore more widely applicable. It is also more precise. 5. Good agreement has been obtained between a chick bioassay and the modified Tetrahymena assay for available lysine in eight different proteins, including heat-damaged fish meals. 6. The modified procedure appeared to give good results for available tryptophan and methionine. 7. When cystine was omitted from the standard culture medium it was possible to test for available methionine plus cystine, but further work is required to assess the reliability of this particular assay.

Evaluation of the Chick Bio-Assay for Estimating Sulfur Amino Acid, Lysine, and Tryptophan Availability in Soybean Meal

Chick growth assays based on 9 to 13 day, 9 to 15 day and 9 to 17 day posthatching weight gains were used to determine the effect of the bio-assay time periods, using the slope-ratio technique, on the relative availability of sulfur amino acids, lysine, and tryptophan in soybean meal. Eight day bio-assays produced the highest availability estimates. Availability estimates for sulfur amino acids, lysine, and tryptophan in soybean meal were 88.46% (8 day-bioassay) vs. 74.41% (4 day-bioassay), 83.23% (8 day-bioassay) vs. 77.42% (6 day-bioassay) and 90.02% (8 day-bioassay) vs. 86.66% (6 day-bioassay), respectively. By measuring growth response of chicks fed reference standard diets as compared with that of chicks fed control diets containing equivalent levels of amino acids determined in soybean meal, the effect of excess amino acids in soybean meal on the sulfur amino acid availability estimate for soybean meal was determined. Excess amino acids did not influence the availability estimate for sulfur amino acids in soybean meal. The relative sulfur amino acid availability estimates of chicks fed excess crystalline amino acids which simulated the amino acidcomposition of soybean meal was 100.96%, as compared with 88.46% for the relative sulfur amino acid and availability estimate for soybean, as determined by the slope-ratio technique.

Chick bioassay of available methionine and methionine plus cystine. Assay of whole egg, fish meal and caseins.

AbstractA chick bioassay procedure1 has been used to determine the relative potency of several animal protein concentrates based on live‐weight gains, food conversion efficiency (FCE) or nitrogen retention. In general, the assays were statistically valid and the majority had 95% fiducial limits as narrow as 88–114%. Expressing response as FCE or nitrogen retention did not give better precision than using weight gain alone. The results showed that there are wide differences in available methionine and SAA in fish meals marketed under same the name.

Chick bioassay of available methionine and sulphur amino acids (SAA). Assay of African oil bean meal (Pentaclethra macrophylla Benth), conophor seed meal (Tetracarpidium conophorum, Hutch) and groundnut meals (Arachis hypogeae Linn).

AbstractAvailable methionine and sulphur amino acids (SAA) were determined in a range of plant protein concentrates using a chick assay procedure described in our first paper1 in this series. There were more instances of invalid assays in plant proteins than in proteins of animal origin.2 This tended to indicate that the procedure is not suitable for estimating available methionine and SAA in plant proteins of low SAA content. Potencies of groundnut meals and conophor seed meal in terms of methionine were high but their available SAA were low. It appears from our results that the inferiority of plant proteins when compared with animal protein concentrates cannot be explained in terms of unavailable methionine but on the inadequacy of the total content of methionine in the plant materials.

Chick bioassay of available methionine and methionine plus cystine. Development of assay procedure.

AbstractA series of experiments has been conducted with young chicks to establish a valid assay procedure1 for assessing available sulphur amino acids (SAA) in protein concentrates. A basal diet was established in which soya bean meal provided 20% crude protein. This diet was shown to be limiting in only SAA. When adequately supplemented with methionine or methionine plus cystine it promoted excellent chick growth. The adaptation of the diet for the assay purposes is described. The linear portion of the regression curve of response on a logarithmic dose scale for methionine alone was found to lie between 0.015 and 0.25%; and 0.009 and 0.09% for methionine in the presence of 0.4% cystine. These regions constituted the potential ranges for the bioassay of methionine and SAA.

Fish Gonadotropin(s). I. Bioassay of Salmon Gonadotropin(s)In vitrowith Immature Trout Gonads

1. The effect of salmon gonadotropin(s) (SG) on cyclic AMP (cAMP) levels in immature trout gonadal tissue of both sexes was measured by radioimmunoassay. 2. A dose-response line was obtained to SG in gonads of both male and female trout. 3. As little as 0.45 SG units (1 SG unit = 1 mug NIH-LH-S18 in the chick bioassay) significantly increased cAMP formation in the presence of 8 mM theophylline; mammalian LH, FSH, LTH, ACTH, TSH and HCG were inactive. 4. The assay for SG was investigated with respect to time of incubation and two phosphodiesterase inhibitors; some conditions for the cAMP radioimmunoassay (cAMP-RIA) were compared.

Vitamin K1 Content of Infant Formula Products

Milk-substitute formulas have been implicated in hypoprothrombinemia in infants and the Committee on Nutrition, AAP, has recommended that those low in vitamin K be supplemented with vitamin K1. A recently developed chromatographic procedure was used to survey the amount of vitamin K1 in commercially available infant formula products. Milk-substitute formulas containing soy oil provided appreciable vitamin K, i.e., 79 to 118µg/liter (as fed), even without vitamin K1 added. Formulas to which vitamin K1 have been added contain from 118 to 256µg/liter. Milk-based formulas contain from 19 to 69µg/liter (depending on the type of oil used), but these have not been implicated in hypoprothrombinemia. According to chick bioassay, vitamin K1 added to infant formula products is biologically available.

Comparative Nutritional Value of Different Cereal Grains as Protein Sources in a Modified Chick Bioassay

Two experiments were conducted using low protein diets to assay the nutritive value of different grains for young chicks. The bioassay used was a modification of the PER method to consider special characteristics of the chick as an experimental subject. In the first experiment a total of 10 samples, including soybean meal, casein, rye, triticale and different selections of corn, wheat and barley were assayed with and without a combined supplement of lysine and procaine penicillin. In the second experiment a total of 23 samples, including soybean meal, casein, rye and different selections of corn, wheat, triticale, barley and sorghum were assayed with and without a lysine supplement. Some of the samples were also assayed with a combined supplement of lysine and procaine penicillin. In all treatments in both experiments the level of total protein in the diet was kept at 14% with 8% supplied by a basal protein premix and the remainder by the test material, with adjustments whenever the lysine supplement was used. Data on body weight and feed consumption of the birds were collected to two weeks of age. PER values were calculated.The results showed soybean meal to have the highest nutritional value of the materials tested. Samples of opaque-2 corn were better than samples of normal corn, even after a lysine deficiency was corrected. A sample of floury-2 corn was only slightly better than its normal counterpart. INIA-66 wheat was better than three other wheat samples, but only after a lysine deficiency was corrected. Triticale (Trailblazer) had a lower PER value than three other triticale selections, but only when the diets contained a supplement of lysine. Hyproly barley gave better growth and PER values than Piroline barley, but supplements of lysine and procaine penicillin made them equal. No differences were observed in the nutritional value of three sorghum samples.

Role of Protein Content, Nitrogen Absorbability and Availability of Carbohydrates in Rapeseed Meal on its Metabolizable Energy Value for Chicks

Experiments were conducted to examine the role of protein content, nitrogen absorbability and available carbohydrates on the metabolizable energy value of rapeseed meal.Percent nitrogen absorbability for one sample of SBM was found to be 84.2 and for three samples of RSM the values averaged 76.1%. The average available carbohydrate content, determined by chick bioassay was found to be 12.2% for the SBM sample and 4.3, 4.0 and 6.4% for the three RSM samples studied.Differences in the M.E. content of the SBM sample and the RSM samples when the M.E. was determined on a feeding regimen in which all the protein was supplied by either SBM or RSM, were 752, 671 and 767 kcal./kg. for the three RSM samples. Of this, the M.E. difference attributable to the lower protein content and the lower nitrogen absorbability in RSM as compared to that of SBM was found to be 497, 370 and 575 kcal./kg. for the three RSMs. Differences in available carbohydrate content of the two protein sources accounted for 288, 302 and 212 kcal./kg. for the three RSM samples.The summation of the quantitative effects of absorbable nitrogen and available carbohydrate in the RSM samples gave totals of 785, 672 and 787 kcal./kg. as against determined differences of 752, 671 and 767 kcal./kg. It is evident therefore, that the lower M.E. of these samples of RSM could be fully accounted for by the above factors and it appears that others had little or no effect on the M.E. content of the meals.

Failure of TRH (Thyrotropin—Releasing Hormone) to Stimulate Thyroid. Function in the Chick

The effect of synthetic TRH (L— (Pyro)Glu—L—His—L—Pro(NH2)) on the release of TSH from the pituitary was observed in the mouse TSH bioassay by measuring 125I release from the thyroid gland. Two different synthetic TRH preparations stimulated TSH release. This bioassay showed a dose—related response at doses larger than 20 ng of TRH. The response was the same after ip or iv injection. The stimulating effects of these synthetic TRH preparations also were examined in a chick bioassay for TSH in which the release of 125I from the thyroid is measured. The synthetic TRH preparations known to be active in the mouse and human were not active in the chick bioassay. In amounts 250–fold greater than the dose required for an active response in the mouse, no thyroid stimulating effects were noted at 2.5 or 8 hr in the chick. These results suggest that synthetic TRH (L—(Pyro)Glu— L—His—L—Pro(NH2)) responses may only be active in mammalian species. (Endocrinology 91: 832, 1972)

Chemical Determination of Available Carbohydrates in Rapeseed Meal

Samples of commercially processed rapeseed meal were analysed for carbohydrates by the anthrone method of Clegg (1956), the Fehling reagent method of Bolton (1960), the glucostat method of Keston (1956) and by the chick bioassay method of Lodhi et al. (1969). The chemical methods were found to grossly overestimate the available carbohydrates in the meals.

A Chick Bioassay for Evaluating the Protein Quality of Dry Breakfast Cereals

Woodham (1968) has described a chick growth test of the protein efficiency ratio (PER) type for evaluating the protein quality of protein supplements in cerealbased diets. In this approach, the total protein efficiency (TPE) of the test supplement is calculated as the weight gain of the chicks divided by the total weight of the protein (supplemental plus background) consumed. The TPE technique may be utilized for protein supplements containing from 20 to 100% of crude protein and has the advantage of being applicable to the evaluation of poor quality proteins which cannot be evaluated by the conventional PER procedure because of their inability to support growth when used as the sole source of dietary protein.The recent attention drawn by Choate (1970) to the nutritive characteristics of dry breakfast cereals (DBC) emphasizes the need for biological assays as opposed to nutritional evaluations based solely upon the percentage of a nutrient…

Pentosans in Prepress-Solvent and Solvent Processed Rapeseed Meal

In studies of factors which cause rapeseed meal to have a lower metabolizable energy value than soybean meal Lodhi et al. (1969) reported that the “available carbohydrate” in rapeseed meal, whether measured chemically or by chick bioassay was less than in soybean meal. During the course of further studies in our laboratories the pentosan content of fifteen samples of rapeseed meal was determined by the A.O.A.C. (1965) method.The results, presented in Table 1, show that eight samples of prepress-solvent meal had an average pentosan content of 8.4% and seven samples of solvent meal had an average pentosan content of 8.3% with an overall average for all meals analyzed of 8.3%.Bolton (1957) reported that the pentosan content of soybean meal was 5.6%. Since the digestibility of pentosans by young chick is negligible (Bolton, 1955), the higher content of this fraction in rapeseed than in soybean meal would appear to…

Mineral Mixture Composition—A Factor in Chick Bioassays of the Protein Quality of Fish Meals

MILLER and Kifer (1970b) showed that the evaluation of the quality of the protein in fish meal, when the meal was fed as the sole source of protein, was influenced by excesses of lysine present in fish meal over the concentration needed in the diet and by various anionic components in the mineral mixture. The excess of lysine was overcome by a dilution of the concentration of lysine in the diet by the addition of glutamic acid (free-base form) or was overcome by counteraction from the addition of arginine. The excess of anionic components was overcome by the inclusion in the diet of the antiacids Al(OH)3 and NaHC03. The detrimental anionic effect was evident when the addition of HCl salt of glutamic acid depressed growth. In contrast, the free-base form of glutamic acid improved growth significantly, owing to two possibilities: (1) the elimination of the detrimental HCl portion of this…