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Riboflavin Requirement of Starting Chickens in a Tropical Environment
Riboflavin Requirement of Starting Chickens in a Tropical Environment B.
K.
OGUNMODEDE
Department of Animal Science, University of Ibadan, Ibadan, Nigeria (Received for publication June 17, 1976)
POULTRY SCIENCE 56: 231-234, 1977
INTRODUCTION
T
HE deficiency of riboflavin in the diet of chicks is manifested by the characteristic symptom of "curled-toe paralysis," but this type of paralysis may not be a fool-proof symptom of riboflavin deficiency as Bird et al. (1946) observed curled-toe paralysis in 20% of their experimental birds. However, slow growth and diarrhea have also been shown by Lepkovsky and Jukes (1936) and Wyatt et al. (1973) to occur when there is inadequate intake of riboflavin. In the tropics, the growth rate of chicks is usually lower than that obtained in the temperate zone. Several reasons may be advanced for the observation. Thus Scott et al. (1969) pointed out that birds consume less feed in a hot environment. Attempts by Mba et al. (1974) and Ogunmodede (1974) to ensure a better body weight gain of birds in a hot climate concentrated on increasing the protein level of the diet, but Chou et al. (1971) showed that the utilization of both energy and protein by growing chicks was decreased when inadequate level of riboflavin was present in the diet. Consequently attention is also being directed towards the vitamin intake by the birds. Because riboflavin is known to be light sensitive, the amounts lost as a result of 231
exposure of the feed were determined. In addition, a study of the feed intake, riboflavin consumption and riboflavin requirements of growing chickens in a tropical environment was undertaken. MATERIALS AND METHODS In the preliminary study, 150 day old straight run Harco chicks were divided into six groups of twenty-five birds per group. They were housed in tier brooder cages with water and feed being available ad libitum. Table 1 shows the composition of the basal ration which was supplemented with 3.6 mg. of riboflavin per kg. of the ration. Routine veterinary care of the birds was also undertaken. For two weeks, the remaining feed in the feeding troughs was removed at daily intervals and the riboflavin content was determined almost immediately by the fluorometric method described by the Association of Vitamin Chemists (1966). Thus the loss of riboflavin in the exposed ration during the twenty-four hour interval was observed to vary between 12 and 17% of the original riboflavin activity. The level of 3.6 mg. riboflavin per kg. of diet was fed as recommended by the National Research Council (1971). In the first experiment 4 groups of Harco day old chicks with 50 chicks per group
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
ABSTRACT Growth rate of broiler chicks tends to be lower in the tropics than in the temperate zone. Results show that up to 17% of dietary riboflavin is destroyed within 24 hours of exposure of the feed to light hence the level of 3.6 mg. of vitamin B 2 recommended does not meet the requirement for growth of broilers. Growth study as well as accumulation of riboflavin in meat and organs of the birds showed that increasing levels of dietary riboflavin increases its deposition in meat and organs of the birds. Optimum growth of birds and storage of riboflavin in the body is attained in the tropical environment when 5.1 mg. of the vitamin is added per kg. of practical ration.
232
B. K. OGUNMODEDE
TABLE 1.—Percentage composition of basal ration 50 30 5 5 3 1.5 2.0 1.5 0.35 0.5 0.5 0.65 +
*The mixture was formulated to the specification by Scott et al. (1969). **Four grams of the commercial antibiotics grains were added to every 4 liters of drinking water. were fed the basal ration without supplementary riboflavin while another two groups received 3.6 mg. of riboflavin per kg. of the compounded ration. After two weeks, when most of the birds in the first 4 groups showed signs of leg weakness, they were given rations containing riboflavin. Riboflavin at the levels of 3.6 mg./kg. and 4.1 mg./kg. of the compounded ration was added such that one group received 4.1 mg. and another 3.6 mg./kg. of feed throughout. The third group received 4.1 mg./kg. of feed for 3 weeks and 3.6 mg./kg. for the last 3 weeks while the fourth group received 3.6 mg./kg. for 3 weeks and 4.1 mg./kg. for the last 3 weeks. However, one of the groups given 3.6 mg./kg. from day old was changed to 4.1 TABLE 2.—Effects
RESULTS AND DISCUSSIONS Records of feed consumption during the first experiment showed no significant differences in feed intake. But the body weights of the birds varied as shown in Table 2. By the end of the first two weeks, birds given no supplemental riboflavin showed signs of deficiency and this was reflected in their weights. When the birds were 5 weeks old those given 3.6 mg. of riboflavin per kg. of diet after depletion were significantly lighter than those given 4.1 mg./kg. At this stage one group given 4.1 mg./kg. after depletion was converted to 3.6 mg./kg. and another group given 3.6 mg./kg. after depletion was
of riboflavin on chick growth in the tropics (gm.)*
Age (weeks) Treatment 5 3.6 mg. riboflavin (+) after depletion 70 426a 840a 519b 961b 4.1 mg. riboflavin (+) after depletion 72 3.6 mg. riboflavin after depletion and (+) 4.1 mg. for the last 3 weeks 68 445a 900ab 4.1 mg. riboflavin after depletion and (+) 3.6 mg. for the last 3 weeks 70 497b 875a 3.6 mg. riboflavin 84 570c 982bc 3.6 mg. riboflavin for 5 weeks and 4.1 mg. for the last 3 weeks. 1074c 91 556c (+) Groups identified received no supplemental riboflavin for the first two weeks of the experiment. **(Means in the same vertical column not marked by the same suffix are significantly different at 5%).
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
Maize Groundnut cake Palm oil Whole milk powder Blood meal Rice bran Oyster shell Bone and meat meal Salt Methionine Lysine Synthetic vitamins and minerals* (riboflavin free) Terramycin (water soluble)**
mg./kg. after 5 weeks. For the entire six weeks records of feed consumption and body weights of the birds were kept. In the second experiment, five groups of day old Harco chicks with 50 birds per group were depleted by being given the basal ration for 14 days after which feeds containing riboflavin at3.6,4.1,5.1,6.1 and7.1 mg./kg., respectively, were given for 6 weeks. The body weight and feed consumption records were kept. At the end of the period 10 birds from each group were slaughtered and the heart, gizzard, liver, breast and leg muscles were excised and weighed. Riboflavin was determined in the meat and organs as described by Peterson et al. (1943).
233
RIBOFLAVIN REQUIREMENT
TABLE 3.—Live weight of chickens on varying dietary riboflavin (gms.)** Mg. Age (weeks) riboflavin/kg. 8 4 6 2 of diet 598a 760a 993a 135a 3.6 158b 630ab 852b 1210b 4.1 660b 937c 1358c 176c 5.1 165b 665b 925c 1370c 6.1 142ab 660b 940c 1332c 7.1 ** Means in the same vertical column not marked by the same suffix are significantly different at 5%.
In the second experiment three higher levels of dietary riboflavin were studied in addition to the previous two. Feed consumption data did not show significant differences but the weekly body weights varied as shown in Table 3. Feeding 3.6 mg. riboflavin per kg. of the ration appeared not to allow a full expression of the growth potential of the birds. This is understandable as the first
REFERENCES Association of Vitamin Chemists Inc., 1966. Methods of Vitamin Assay. Interscience Publishers. New York. pp. 158-164. Bird, F. H., V. S. Asmundson, F. H. Kratzer, and S. Lepkovsky, 1946. The comparative requirements of chicks and turkey poults for riboflavin. Poultry Sci. 25: 47-51. Chou, S. T., J. L. Sell and P. A. Kondra, 1971.
TABLE 4.—Storage of riboflavin in chicken meat (microgram per gram fresh weight)** Dietary riboflavin (mg./kg. of diet) 3.6 4.1 5.1 6.1 7.1 **Means in the same vertical at 5%.
Heart Gizzard Breast 3.3a 7.8a 0.4a 13.0b 4.1b 0.6b 18.4c 5.5c 0.9c 19.2c 5.5c 1.0c 20.6c 5.9c 1.2d column not marked by the same suffix are
Liver 21.4a 29.8b 34.6c 35.2 34.8c significantly
Leg 1.7a 3.1b 4.6c 4.8c 5.1c different
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
converted to 4.1 mg./kg. At the end of an additional 3 weeks that is when the birds were 8 weeks old those switched from 3.6 mg./kg. to 4.1 mg./kg. had slightly higher body weights than those switched from 4.1 mg. to 3.6 although the differences were not statistically significant. It was felt that the time lapse during the change over was short and that studies of these levels over a longer period of time was necessary. Similar results were obtained when birds given 3.6 mg. of riboflavin per kg. of diet for the first 5 weeks of life were changed to 4.1 mg. for 3 weeks. That is changing to a higher dietary riboflavin level tended to stimulate higher growth.
experiment showed that there is marked loss of the vitamin from the diet as a result of exposure. The administration of 4.1 mg. of riboflavin per kg. of the diet improved the live weight gain while a level of 5.1 mg. of the vitamin further improved the body weight gain. However, raising the level or riboflavin to 6.1 and 7.1 mg./kg. of diet, respectively, did not improve the gain above that of 5.1. Thus a level of 5.1 mg. of the vitamin per kg. of diet appears to be necessary to obtain maximum growth potential of the birds under the condition of the experiment. The increased production of meat should be accompanied by improvement of quality in order to attain better nutrition to consumers. Therefore the meat of birds on different riboflavin intake was analysed at the end of the second experiment. Results in Table 4 show that increasing the dietary intake of the vitamin led to greater accumulation of riboflavin in the meat. However, feeding the vitamin at a level higher than 5.1 mg. per kg. of diet did not stimulate higher deposition of the vitamin both in the meat and organs of chickens.
234
B . K. OGUNMODEDE
Ogunmodede, B. K., 1974. Dietary zinc and protein utilization by growing chickens. Nig. J. Anim. Prod. 1(2): 198-203. Peterson, W. J., D. E. Brady and A. O. Shaw, 1943. Fluorometric determination of riboflavin in pork products. Ind. Eng. Chem. Anal. Ed. 15: 634-636. Scott, M. L., M. C. Nesheim and R. J. Young, 1969. Nutrition of the Chicken. M. L. Scott and Associates, Ithaca, New York, p. 49, 428. Wyatt, R. D., H. T. Tung, W. E. Donaldson and P. B. Hamilton, 1973. A new description of riboflavin deficiency syndrome in chickens. Poultry Sci. 52: 237-244.
The Effect of Luteinizing Hormone Releasing Hormone (L.H.R.H.) on Serum L.H. and Ovarian Growth in Turkeys* W . H . BURKE AND E . A. COGGER
Department of Animal Science, University of Minnesota, St. Paul, Minn. 55108 (Received for publication June, 23, 1976)
ABSTRACT Serum L.H. of non-laying turkey hens (NL.) was significantly higher than serum LH of layers (L.). All NL. hens showed a marked increase in serum L.H. within 5 min. of an i.v. injection of 20 or 40 u.g. of L.H.R.H. The L.H. levels of NL. hens were significantly lower at 15 min. after L.H.R.H. injection than at 5 min. The laying turkeys were erratic in their response, with clear cut, small rises in L.H. occurring only in some individuals with hard shelled eggs in utero. Hens with membranous eggs or with empty uteri failed to respond to the L.H.R.H. While F.S.H./L.H. injections caused significant ovarian and oviducal growth, L.H.R.H. given by daily i.m. injection for 7 days or twice daily i.v. injection for 6 days failed to do so. Subcutaneous implants of 1 mg. of L.H.R.H. in polyacrylamide gel led to prolonged elevation in serum L.H.R.H. and increased serum L.H. for about 12 hr. but caused no change in ovarian or oviducal weights. POULTRY SCIENCE 56: 234-242, 1977
T
HE avian hypothalamic factor which causes the release of luteinizing hormone (L.H.) has been shown to be chromatographically and immunologically indistinguishable from synthetic luteinizing hormone releasing hormone (L.H.R.H.) (Jeffcoate et ai, 1974). Synthetic L.H.R.H. induces ovulation in chickens (van Tienhoven and Schally, 1973; Reeves et ai, 1973), elicits the release of gonadotropins from chicken pituitary glands in vitro (Tanaka et ai, 1974),
1. Scientific Journal Series Paper Number 9578, of the Minnesota Agricultural Experiment Station.
causes a rapid rise in serum L.H. when injected into chickens (Furr et ai, 1973; Bonney et ai, 1974) and induces testicular growth in Coturnix quail when they are maintained on a 15 hr. daily light regime and treated with a drug to depress testis growth (El Halawani and Burke, 1975) but not on a 6 hr. light regime (Burke et ai, unpublished observations; Wada, 1975). Reeves et al. (1973) were unable to induce ovarian growth with L.H.R.H. in mature chickens made sexually inactive by reducing the photoperiod from 15 hr. to 6 hr. per day. It was the purpose of this study to determine the effects of L.H.R.H. on serum L.H.
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
Interrelationships between riboflavin and dietary energy and protein utilisation in growing chicks. Br. J. Nutr. 26: 323-333. Lepkovsky, S., and T. S. Jukes, 1936. The response of rats, chicks and turkey poults to crystalline vitamin G (flavin). J. Nutr. 12: 515-526. Mba, A. U., A. O. Bello, V. A. Oyenuga and F. O. Olubajo, 1974. The effects of varying the levels of proteins and red palm oil on the utilization of poultry feeds by broiler chicks. Niger. Agric. J. 11(2): 174-184. National Research Council, 1971. Nutrient requirements of poultry. National Academy of Sciences.
K.
OGUNMODEDE
Department of Animal Science, University of Ibadan, Ibadan, Nigeria (Received for publication June 17, 1976)
POULTRY SCIENCE 56: 231-234, 1977
INTRODUCTION
T
HE deficiency of riboflavin in the diet of chicks is manifested by the characteristic symptom of "curled-toe paralysis," but this type of paralysis may not be a fool-proof symptom of riboflavin deficiency as Bird et al. (1946) observed curled-toe paralysis in 20% of their experimental birds. However, slow growth and diarrhea have also been shown by Lepkovsky and Jukes (1936) and Wyatt et al. (1973) to occur when there is inadequate intake of riboflavin. In the tropics, the growth rate of chicks is usually lower than that obtained in the temperate zone. Several reasons may be advanced for the observation. Thus Scott et al. (1969) pointed out that birds consume less feed in a hot environment. Attempts by Mba et al. (1974) and Ogunmodede (1974) to ensure a better body weight gain of birds in a hot climate concentrated on increasing the protein level of the diet, but Chou et al. (1971) showed that the utilization of both energy and protein by growing chicks was decreased when inadequate level of riboflavin was present in the diet. Consequently attention is also being directed towards the vitamin intake by the birds. Because riboflavin is known to be light sensitive, the amounts lost as a result of 231
exposure of the feed were determined. In addition, a study of the feed intake, riboflavin consumption and riboflavin requirements of growing chickens in a tropical environment was undertaken. MATERIALS AND METHODS In the preliminary study, 150 day old straight run Harco chicks were divided into six groups of twenty-five birds per group. They were housed in tier brooder cages with water and feed being available ad libitum. Table 1 shows the composition of the basal ration which was supplemented with 3.6 mg. of riboflavin per kg. of the ration. Routine veterinary care of the birds was also undertaken. For two weeks, the remaining feed in the feeding troughs was removed at daily intervals and the riboflavin content was determined almost immediately by the fluorometric method described by the Association of Vitamin Chemists (1966). Thus the loss of riboflavin in the exposed ration during the twenty-four hour interval was observed to vary between 12 and 17% of the original riboflavin activity. The level of 3.6 mg. riboflavin per kg. of diet was fed as recommended by the National Research Council (1971). In the first experiment 4 groups of Harco day old chicks with 50 chicks per group
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
ABSTRACT Growth rate of broiler chicks tends to be lower in the tropics than in the temperate zone. Results show that up to 17% of dietary riboflavin is destroyed within 24 hours of exposure of the feed to light hence the level of 3.6 mg. of vitamin B 2 recommended does not meet the requirement for growth of broilers. Growth study as well as accumulation of riboflavin in meat and organs of the birds showed that increasing levels of dietary riboflavin increases its deposition in meat and organs of the birds. Optimum growth of birds and storage of riboflavin in the body is attained in the tropical environment when 5.1 mg. of the vitamin is added per kg. of practical ration.
232
B. K. OGUNMODEDE
TABLE 1.—Percentage composition of basal ration 50 30 5 5 3 1.5 2.0 1.5 0.35 0.5 0.5 0.65 +
*The mixture was formulated to the specification by Scott et al. (1969). **Four grams of the commercial antibiotics grains were added to every 4 liters of drinking water. were fed the basal ration without supplementary riboflavin while another two groups received 3.6 mg. of riboflavin per kg. of the compounded ration. After two weeks, when most of the birds in the first 4 groups showed signs of leg weakness, they were given rations containing riboflavin. Riboflavin at the levels of 3.6 mg./kg. and 4.1 mg./kg. of the compounded ration was added such that one group received 4.1 mg. and another 3.6 mg./kg. of feed throughout. The third group received 4.1 mg./kg. of feed for 3 weeks and 3.6 mg./kg. for the last 3 weeks while the fourth group received 3.6 mg./kg. for 3 weeks and 4.1 mg./kg. for the last 3 weeks. However, one of the groups given 3.6 mg./kg. from day old was changed to 4.1 TABLE 2.—Effects
RESULTS AND DISCUSSIONS Records of feed consumption during the first experiment showed no significant differences in feed intake. But the body weights of the birds varied as shown in Table 2. By the end of the first two weeks, birds given no supplemental riboflavin showed signs of deficiency and this was reflected in their weights. When the birds were 5 weeks old those given 3.6 mg. of riboflavin per kg. of diet after depletion were significantly lighter than those given 4.1 mg./kg. At this stage one group given 4.1 mg./kg. after depletion was converted to 3.6 mg./kg. and another group given 3.6 mg./kg. after depletion was
of riboflavin on chick growth in the tropics (gm.)*
Age (weeks) Treatment 5 3.6 mg. riboflavin (+) after depletion 70 426a 840a 519b 961b 4.1 mg. riboflavin (+) after depletion 72 3.6 mg. riboflavin after depletion and (+) 4.1 mg. for the last 3 weeks 68 445a 900ab 4.1 mg. riboflavin after depletion and (+) 3.6 mg. for the last 3 weeks 70 497b 875a 3.6 mg. riboflavin 84 570c 982bc 3.6 mg. riboflavin for 5 weeks and 4.1 mg. for the last 3 weeks. 1074c 91 556c (+) Groups identified received no supplemental riboflavin for the first two weeks of the experiment. **(Means in the same vertical column not marked by the same suffix are significantly different at 5%).
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
Maize Groundnut cake Palm oil Whole milk powder Blood meal Rice bran Oyster shell Bone and meat meal Salt Methionine Lysine Synthetic vitamins and minerals* (riboflavin free) Terramycin (water soluble)**
mg./kg. after 5 weeks. For the entire six weeks records of feed consumption and body weights of the birds were kept. In the second experiment, five groups of day old Harco chicks with 50 birds per group were depleted by being given the basal ration for 14 days after which feeds containing riboflavin at3.6,4.1,5.1,6.1 and7.1 mg./kg., respectively, were given for 6 weeks. The body weight and feed consumption records were kept. At the end of the period 10 birds from each group were slaughtered and the heart, gizzard, liver, breast and leg muscles were excised and weighed. Riboflavin was determined in the meat and organs as described by Peterson et al. (1943).
233
RIBOFLAVIN REQUIREMENT
TABLE 3.—Live weight of chickens on varying dietary riboflavin (gms.)** Mg. Age (weeks) riboflavin/kg. 8 4 6 2 of diet 598a 760a 993a 135a 3.6 158b 630ab 852b 1210b 4.1 660b 937c 1358c 176c 5.1 165b 665b 925c 1370c 6.1 142ab 660b 940c 1332c 7.1 ** Means in the same vertical column not marked by the same suffix are significantly different at 5%.
In the second experiment three higher levels of dietary riboflavin were studied in addition to the previous two. Feed consumption data did not show significant differences but the weekly body weights varied as shown in Table 3. Feeding 3.6 mg. riboflavin per kg. of the ration appeared not to allow a full expression of the growth potential of the birds. This is understandable as the first
REFERENCES Association of Vitamin Chemists Inc., 1966. Methods of Vitamin Assay. Interscience Publishers. New York. pp. 158-164. Bird, F. H., V. S. Asmundson, F. H. Kratzer, and S. Lepkovsky, 1946. The comparative requirements of chicks and turkey poults for riboflavin. Poultry Sci. 25: 47-51. Chou, S. T., J. L. Sell and P. A. Kondra, 1971.
TABLE 4.—Storage of riboflavin in chicken meat (microgram per gram fresh weight)** Dietary riboflavin (mg./kg. of diet) 3.6 4.1 5.1 6.1 7.1 **Means in the same vertical at 5%.
Heart Gizzard Breast 3.3a 7.8a 0.4a 13.0b 4.1b 0.6b 18.4c 5.5c 0.9c 19.2c 5.5c 1.0c 20.6c 5.9c 1.2d column not marked by the same suffix are
Liver 21.4a 29.8b 34.6c 35.2 34.8c significantly
Leg 1.7a 3.1b 4.6c 4.8c 5.1c different
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
converted to 4.1 mg./kg. At the end of an additional 3 weeks that is when the birds were 8 weeks old those switched from 3.6 mg./kg. to 4.1 mg./kg. had slightly higher body weights than those switched from 4.1 mg. to 3.6 although the differences were not statistically significant. It was felt that the time lapse during the change over was short and that studies of these levels over a longer period of time was necessary. Similar results were obtained when birds given 3.6 mg. of riboflavin per kg. of diet for the first 5 weeks of life were changed to 4.1 mg. for 3 weeks. That is changing to a higher dietary riboflavin level tended to stimulate higher growth.
experiment showed that there is marked loss of the vitamin from the diet as a result of exposure. The administration of 4.1 mg. of riboflavin per kg. of the diet improved the live weight gain while a level of 5.1 mg. of the vitamin further improved the body weight gain. However, raising the level or riboflavin to 6.1 and 7.1 mg./kg. of diet, respectively, did not improve the gain above that of 5.1. Thus a level of 5.1 mg. of the vitamin per kg. of diet appears to be necessary to obtain maximum growth potential of the birds under the condition of the experiment. The increased production of meat should be accompanied by improvement of quality in order to attain better nutrition to consumers. Therefore the meat of birds on different riboflavin intake was analysed at the end of the second experiment. Results in Table 4 show that increasing the dietary intake of the vitamin led to greater accumulation of riboflavin in the meat. However, feeding the vitamin at a level higher than 5.1 mg. per kg. of diet did not stimulate higher deposition of the vitamin both in the meat and organs of chickens.
234
B . K. OGUNMODEDE
Ogunmodede, B. K., 1974. Dietary zinc and protein utilization by growing chickens. Nig. J. Anim. Prod. 1(2): 198-203. Peterson, W. J., D. E. Brady and A. O. Shaw, 1943. Fluorometric determination of riboflavin in pork products. Ind. Eng. Chem. Anal. Ed. 15: 634-636. Scott, M. L., M. C. Nesheim and R. J. Young, 1969. Nutrition of the Chicken. M. L. Scott and Associates, Ithaca, New York, p. 49, 428. Wyatt, R. D., H. T. Tung, W. E. Donaldson and P. B. Hamilton, 1973. A new description of riboflavin deficiency syndrome in chickens. Poultry Sci. 52: 237-244.
The Effect of Luteinizing Hormone Releasing Hormone (L.H.R.H.) on Serum L.H. and Ovarian Growth in Turkeys* W . H . BURKE AND E . A. COGGER
Department of Animal Science, University of Minnesota, St. Paul, Minn. 55108 (Received for publication June, 23, 1976)
ABSTRACT Serum L.H. of non-laying turkey hens (NL.) was significantly higher than serum LH of layers (L.). All NL. hens showed a marked increase in serum L.H. within 5 min. of an i.v. injection of 20 or 40 u.g. of L.H.R.H. The L.H. levels of NL. hens were significantly lower at 15 min. after L.H.R.H. injection than at 5 min. The laying turkeys were erratic in their response, with clear cut, small rises in L.H. occurring only in some individuals with hard shelled eggs in utero. Hens with membranous eggs or with empty uteri failed to respond to the L.H.R.H. While F.S.H./L.H. injections caused significant ovarian and oviducal growth, L.H.R.H. given by daily i.m. injection for 7 days or twice daily i.v. injection for 6 days failed to do so. Subcutaneous implants of 1 mg. of L.H.R.H. in polyacrylamide gel led to prolonged elevation in serum L.H.R.H. and increased serum L.H. for about 12 hr. but caused no change in ovarian or oviducal weights. POULTRY SCIENCE 56: 234-242, 1977
T
HE avian hypothalamic factor which causes the release of luteinizing hormone (L.H.) has been shown to be chromatographically and immunologically indistinguishable from synthetic luteinizing hormone releasing hormone (L.H.R.H.) (Jeffcoate et ai, 1974). Synthetic L.H.R.H. induces ovulation in chickens (van Tienhoven and Schally, 1973; Reeves et ai, 1973), elicits the release of gonadotropins from chicken pituitary glands in vitro (Tanaka et ai, 1974),
1. Scientific Journal Series Paper Number 9578, of the Minnesota Agricultural Experiment Station.
causes a rapid rise in serum L.H. when injected into chickens (Furr et ai, 1973; Bonney et ai, 1974) and induces testicular growth in Coturnix quail when they are maintained on a 15 hr. daily light regime and treated with a drug to depress testis growth (El Halawani and Burke, 1975) but not on a 6 hr. light regime (Burke et ai, unpublished observations; Wada, 1975). Reeves et al. (1973) were unable to induce ovarian growth with L.H.R.H. in mature chickens made sexually inactive by reducing the photoperiod from 15 hr. to 6 hr. per day. It was the purpose of this study to determine the effects of L.H.R.H. on serum L.H.
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSIDAD DE SEVILLA on April 14, 2015
Interrelationships between riboflavin and dietary energy and protein utilisation in growing chicks. Br. J. Nutr. 26: 323-333. Lepkovsky, S., and T. S. Jukes, 1936. The response of rats, chicks and turkey poults to crystalline vitamin G (flavin). J. Nutr. 12: 515-526. Mba, A. U., A. O. Bello, V. A. Oyenuga and F. O. Olubajo, 1974. The effects of varying the levels of proteins and red palm oil on the utilization of poultry feeds by broiler chicks. Niger. Agric. J. 11(2): 174-184. National Research Council, 1971. Nutrient requirements of poultry. National Academy of Sciences.