Search PubMed⌕ Search

Biomedical subjects

I Nir

Publications and source records attributed to I Nir.

At least 19 recordsLinked to original sources
PubMed2004

Reproductive traits in the spur-thighed tortoise (Testudo graeca terrestris): new tools for the enhancement of reproductive success and survivorship.

The Mediterranean tortoise (Testudo graeca) is listed as "Vulnerable" on the IUCN Red List. Reproductive characteristics and means to increase offspring production were studied in T. graeca terrestris in a semi-natural environment. Courtship and mating occurred during early spring for about 4 weeks, followed by a laying season of approximately 2 months, with a second, shorter mating period in the fall. During the first mating, calcified eggs were already present in the uterus; we inferred that sperm from both mating seasons were stored in the oviduct for fertilization of eggs of the second laying cycle and of the following year. Average egg production was 3.8+/-0.3 eggs/year. Most females laid all of their eggs in a single clutch, but 18% laid in a second clutch, 11-21 days later. X-ray radiography revealed calcified eggs in the uterus about 4 weeks before oviposition. All eggs in the uterus were calcified simultaneously and were laid in a single clutch; if a second clutch developed, those eggs were also calcified simultaneously. Based on endoscopic examinations, ovaries were active throughout the entire year. Plasma progesterone concentrations in females were very low and were detected only soon after oviposition ( 440 +/-141 pg/ml). Plasma estradiol concentrations in females varied from 4.1 +/-1.5 pg/ml to 70.2 +/-29.4 pg/ml, with no clear seasonal pattern. Maintaining tortoises at a low environmental temperature (9 +/-1 degrees C versus 28 +/- 1 degrees C) reduced plasma estradiol concentrations. Giving 2mg/kg tamoxifen (TAM) increased plasma estradiol to 220 +/-33 pg/ml when treatment was given in September but not in late October, winter or spring. Treatment with TAM increased the number of eggs laid during the following laying season to 7.3 +/- 1.0 eggs/year, laid in one to three clutches. In males, plasma testosterone concentrations had a seasonal pattern with the onset of a rise in July from 2 to >4ng/ml, a continued increase to a peak of 12.8+/-5.3 ng/ml during November and a decline thereafter. Artificial incubation in sand at 29 +/-1 degrees C shortened the natural incubation time of 103+/-3.1 days to 83.5 +/- 1.3 days, increased hatching rate from 28 to 53%, and increased survival rate from 51 to 71% at 40 weeks of age. In summary, this study provides options for increasing reproductive performance, hatchability and offspring survival in captive Mediterranean tortoises, and may offer new tools for conservation of animals that are on the verge of extinction.

Animals↗
PubMed2001

Regulation of cAMP by light and dopamine receptors is dysfunctional in photoreceptors of dystrophic retinal degeneration slow(rds) mice.

cAMP levels in dark and light were studied in dystrophic retinal degeneration slow(rds) mice, which carry a mutation in the rds/peripherin gene. cAMP levels were measured in vivo, in freshly isolated retinas, and in vitro in the presence of glutamate, which confines light modulation to photoreceptors. Experiments were conducted on young animals, when significant numbers of viable photoreceptor cells are present. In vivo levels of cAMP are higher in illuminated rds/rds retinas than levels measured in normal BALB/c retinas. Light-evoked down-regulation of cAMP levels was observed in vitro in normal photoreceptors. These measurements were made in the presence of the cyclic nucleotide phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine; therefore, they reflect an inhibition of cAMP formation. In contrast, light had no effect on cAMP formation in photoreceptors of mutant mice, measured under identical conditions. Thus, elevated levels of cAMP in rds/rds retinas in vivo result from abnormalities in cAMP synthesis in the mutant photoreceptor cells. In addition to regulation by light, cAMP formation in photoreceptor cells is regulated by dopamine, acting through dopamine D4 receptors. A dopamine D2/D4 receptor agonist, quinpirole, reduced cAMP levels in dark-adapted normal retinas in vitro, but not in rds/rds retinas. Our data indicate that alterations in a signal transduction pathway that leads to inhibition of adenylyl cyclase might underlie the abnormalities in cAMP levels in mutant rds/rds retinas. Heterozygous rds/+ photoreceptors demonstrated a normal pattern of light-evoked and quinpirole-mediated down-regulation of cAMP. Thus, partial expression of the normal phenotype is sufficient to render normal characteristics of cAMP regulation to the photoreceptors of the heterozygous mouse. The data obtained in the present study might be relevant to the understanding of photoreceptor pathology of patients with peripherin/rds mutations.

Adenylyl Cyclases↗
PubMed2001

Extended photoreceptor viability by light stress in the RCS rats but not in the opsin P23H mutant rats.

PURPOSE: To determine the effect of light stress on retinal function and long-term photoreceptor viability in Royal College of Surgeons (RCS) rats and the applicability of the light treatment to the opsin P23H mutant rats. METHODS: RCS rats at postnatal day (P)23 were illuminated with 120 foot-candles (fc) white light for 10 hours. Photoreceptor survival and basic fibroblast growth factor (bFGF) expression were measured at P60 and P83. Retinal function was evaluated by electroretinography. Opsin P23H transgenic rats were treated with light at P28 and analyzed at P70 for photoreceptor viability, ultrastructure, and bFGF expression. RESULTS: Light-treated RCS rats at P60 had four to five rows of nuclei versus one to two rows in untreated littermates. The average amplitude of the ERG b-wave was 28 microV in treated rats, compared with 6 microV in untreated littermates. By P83 there was still significant preservation of the ONL in treated rats. Immunoblot analysis showed a high expression of bFGF in the treated retinas even 2 months after treatment. Illumination of P23H rats at P28 with 120 fc white light for 10 hours caused substantial photoreceptor cell death, although bFGF expression was upregulated. Lowered illumination dosages continued to cause photoreceptor damage until levels were reached that neither caused damage nor enhanced survival. CONCLUSIONS: Although light stress promotes photoreceptor survival and function in the RCS rat, it elicits death signals in the P23H rats that may not be overcome by survival-promoting factors. Therefore, use of light stress to promote photoreceptor survival should be considered with regard to sensitivity of the mutation to light damage.

Animals↗
PubMed2000

Diurnal metabolism of dopamine in dystrophic retinas of homozygous and heterozygous retinal degeneration slow (rds) mice.

Dopamine metabolism was studied in dystrophic retinal degeneration slow (rds) mice which carry a mutation in the rds/peripherin gene. RDS mutations in humans cause several forms of retinal degeneration. Dopamine synthesis and utilization were analyzed at various time points in the diurnal cycle in homozygous rds/rds retinas which lack photoreceptor outer segments and heterozygous rds/+ retinas which have short malformed outer segments. Homozygous retinas exhibited depressed dopamine synthesis and utilization while the heterozygous retina retained a considerable level of activity which was, nevertheless, significantly lower than that of normal retinas. By one year, heterozygous rds/+ retinas which had lost half of the photoreceptors still maintained significant levels of dopamine metabolism. Normal characteristics of dopamine metabolism such as a spike in dopamine utilization at light onset were observed in mutant retinas. However, light intensity-dependent changes in dopamine utilization were observed in normal but not rds/+ retinas. The findings of this study suggest that human patients with peripherin/rds mutations, or other mutations that result in abnormal outer segments that can still capture light, might maintain light-evoked dopamine metabolism and dopamine-dependent retinal functions during the progression of the disease, proportional to remaining levels of light capture capabilities. However, visual deficits due to reduced light-evoked dopamine metabolism and abnormal patterns of dopamine utilization could be expected in such diseased retinas.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

Diurnal metabolism of dopamine in the mouse retina.

Dopamine is an important retinal neurotransmitter and neuromodulator that regulates key diurnal cellular and physiological functions. In the present study we carried out a comprehensive analysis of dopamine metabolism during the light phase of the diurnal cycle and evaluated the presence of diurnal and circadian rhythms of dopaminergic activity in the mouse retina. Steady-state levels of dopamine did not change significantly between the dark phase (night) and the light phase (day) of the diurnal cycle, nor did they change between early and late points in the day. Dopamine synthesis and utilization, however, revealed significant alterations between the night and day and between early and late time points in the day. A spike in synthesis and utilization was measured immediately after light onset at the end of the night. Subsequently, dopamine synthesis and utilization partially declined and remained stable throughout the remainder of the day at a level that was significantly higher than that at night. The burst of dopamine synthesis and utilization at the beginning of the day is entirely light evoked and not driven by a circadian clock. Similarly, there was no circadian rhythm in dopamine synthesis and utilization in mice kept in constant darkness. This daily pattern of dopaminergic activity may impact upon a variety of temporally regulated retinal events. Moreover, these data will provide a basis for evaluating the role of dopamine in retinal pathology in mouse models of retinal degeneration where mutations affect light perception.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

Expression of Bcl-2 protects against photoreceptor degeneration in retinal degeneration slow (rds) mice.

The retinal degeneration slow or rds gene encodes rds/peripherin, an integral membrane glycoprotein in the outer segments of rod and cone photoreceptors. Mice homozygous for a null mutation in rds fail to develop outer segments and undergo subsequent degeneration of photoreceptors by the apoptotic pathway. Mutations in the human RDS gene are responsible for several forms of inherited blindness including autosomal-dominant retinitis pigmentosa and macular degeneration. Here, we examined the effects of ectopic Bcl-2 expression in transgenic photoreceptors on the rate of retinal degeneration in rds mutant mice. We observed an approximately twofold preservation of photoreceptors compared with nontransgenic rds mutant mice at 3 months. Immunoblot analysis showed similar levels of Bcl-2 in 2-, 3-, and 4-week-old transgenic mice. Expression of Bcl-2 in the rds mouse did not lead to outer segment formation and did not induce cell death. These results suggest that Bcl-2 expression may be an effective therapeutic strategy in humans with mutations in RDS or other genes that affect the integrity of photoreceptor outer segments.

Animals↗
PubMed1999

Stunting syndrome in broilers: effect of electrolytes in drinking water on performance and intestinal glucose transport.

Posthatched naive or inoculated male broiler chicks were kept in separate rooms. An inoculum was prepared from intestines of stunting-syndrome affected broiler chicks. Tap water was supplied from 2 L cups, 1 cup per pen. In the Ist experiment, the naive chicks were provided with tap water only and the inoculated ones had free access to tap water or to an electrolyte solution. In the 2nd experiment, the naive and inoculated birds had free access to water in addition to an electrolyte solution. Supplementation was provided up to 3 weeks of age; thereafter all chicks had access to tap water only. Water or electrolyte consumption and body weight (BW) were determined. Total water intake of inoculated chicks was higher than that of naive counterparts (P<0.001). Electrolyte supplementation increased drinking (P<0.001) in inoculated birds more than in naive ones. At 1 week old the weight of the inoculated birds was about 64% of the weight of naive ones; at the age of 4 and 6 weeks it was about 74% and 86% respectively. Compensatory growth was most apparent in the inoculated chicks provided with electrolyte solution. At the age of 6 weeks, the latter exceeded the BW of the exclusively water supplied counterparts by 327 g. Electrolyte supplementation up to the age of 3 weeks had no effect on the naive counterparts. Osmolality was reduced slightly, but very significantly by inoculation; electrolyte supply had no effect on this variable. Sodium concentration in the plasma was higher in the inoculated birds. Plasma albumin was markedly reduced by inoculation on weeks 1 and 2. Whereas the inoculated chicks supplied with electrolytes resumed the level plasma albumin level of the naive chicks on week 3, an over-compensation occurred in the inoculated-water-supplied (IW) group, and they surpassed the naive chicks significantly. Blood hematocrit increased significantly with age; inoculation, age and/or electrolyte supplementation had no effect on this variable. Sodium-dependent glucose transport rates were enhanced in vesicles obtained from inoculated chicks as compared to naive ones. While electrolyte supplementation had no effect on glucose active transport in naive chicks, electrolyte supplementation decreased rates of glucose active transport in inoculated ones. These data demonstrate that electrolyte supplementation during the early age may be used to enhance the tolerance of broiler chicks to stunting-syndrome by improving food and water consumption, and subsequently growth rate during and after cessation of electrolyte supply.

Animals↗
PubMed1999

Light treatment enhances photoreceptor survival in dystrophic retinas of Royal College of Surgeons rats.

PURPOSE: To determine whether treatment with bright light elicits a protective response that enhances photoreceptor survival in Royal College of Surgeons (RCS) rats with inherited retinal degeneration. METHODS: RCS rats were illuminated for 10 to 12 hours with 130 foot-candles (fc) of white or green light. Untreated littermates that were kept under low cyclic light levels were used as control subjects. Photoreceptor survival was determined by quantitative analysis of photoreceptor nuclei and ultrastructural assessment of cellular organization. Basic fibroblast growth factor (bFGF) and ciliary neurotrophic factor (CNTF) gene expression were determined at the mRNA and protein levels. RESULTS: Treatments of RCS rats with a single dose of bright light on postnatal day 23 (P23) greatly enhanced photoreceptor survival. Ultrasturctural analysis revealed intact inner segments in light-treated retinas, whereas in untreated retinas only remnants of inner segments were observed. By P42, numerous viable nuclei were counted in the posterior retina of light-treated rats, whereas most of the remaining nuclei in untreated RCS rat retinas were highly pyknotic. At 2.5 days after treatment with a single dose of bright light, bFGF gene expression was significantly higher than in untreated RCS rat retinas. By P42, bFGF protein levels were still significantly higher in the treated retinas. CONCLUSIONS: Exogenous bFGF has been shown to promote photoreceptor survival in the RCS rat retina. Thus, the increased bFGF expression that was measured in the light-treated RCS rat retinas may be a protective response to light stress, which supports the observed rescue of photoreceptors in light-treated RCS rat retinas.

Animals↗
PubMed1998

Stunting syndrome in broilers: effect of stunting syndrome inoculum obtained from stunting syndrome affected broilers, on broilers, leghorns and turkey poults.

Responses to stunting syndrome (SS) infective material obtained from affected broilers and administered per os were monitored for 3 wk in a fast-growing commercial broiler population, in slow-growing Leghorn chicks, and in turkey poults. At 2 and 3 wk, the size of the gastrointestinal tract (GIT) segments, the pH of the GIT contents, and the activities of digestive enzymes in the intestinal contents and of disaccharidases on the jejunum mucosae were determined. Inoculation affected the genetic stocks differently. In broiler chicks, growth and feed utilization were markedly reduced. In contrast, inoculation of Leghorns was accompanied by improved feed intake and growth rate. Performance of poults was affected only slightly, albeit significantly. The effect of inoculation on the pH of crop and intestinal contents in Leghorn chicks was opposite to that found in broiler chicks, i.e., a significant increase in the crop and small intestinal pH in the former vs a significant decrease in inoculated broilers. Although inoculation of the broiler chicks did not affect the pH in the proventriculus, in Leghorn chicks it was reduced by 25%. In poults, inoculation did not significantly affect GIT contents pH. The GIT segments were markedly enlarged in broiler chicks, whereas in Leghorn chicks the opposite trend was observed; namely, intestinal segment weights were significantly reduced. In poults, inoculation caused a reduction in the intestinal segments and gizzard weight at 3 wk. During this same period, the liver and pancreas relative weights were dramatically increased in broiler chicks. A higher relative heart weight at 2 wk was observed in broilers and poults; this trend persisted to Week 3 in poults but not in broiler chicks. In broiler chicks, a nonsignificant reduction was observed for all enzymes assayed at 3 wk and for chymotrypsin at 2 wk. In Leghorn chicks, inoculation was accompanied by a marked and significant increase in the activity of chymotrypsin during both periods. In poults, inoculation caused a marked increase in the activities of amylase during Week 2 and 3, and trypsin at 3 wk. Maltase and saccharase activities in the jejunum of broiler chicks were slightly depressed a t 2 and 3 wk, the depression being significant at 2 wk for maltase and at 3 wk for saccharase. In the Leghorn chicks, inoculation caused a twofold increase in the activities of both enzymes. As in Leghorns, inoculation of poults with SS infective material caused a marked increase in the activities of the disaccharidases. The different responses to SS inoculation in the different genetic stocks are discussed.

Animals↗
PubMed1997

Delayed rhodopsin regeneration and altered distribution of interphotoreceptor retinoid binding protein (IRBP) in the mi(vit)/mi(vit) (vitiligo) mouse.

Rhodopsin regeneration requires attachment between the retinal pigment epithelium (RPE) and rod outer segments; however, in experimentally induced retinal detachment, rhodopsin regeneration can be restored partially upon addition of IRBP (interphotoreceptor retinoid binding protein). The mi(vit)/mi(vit) (vitiligo) mutant mouse, a model of slowly progressing photoreceptor cell degeneration, has a marked elevation of IRBP at 4 weeks as well as progressive detachment of the retina. The purpose of this study was to determine whether this mutant is capable of regenerating rhodopsin within a few hours following an intense light bleach. Rhodopsin regeneration was determined spectrophotometrically in mice after an intense one hour light bleach followed by 0,1,2,4 or 24 h of dark recovery. IRBP was localized immunohistochemically in fixed frozen tissue at the light microscopic level and in LR Gold embedded tissue at the ultrastructural level. Rhodopsin regeneration experiments indicated that rhodopsin levels following 0,1,2 and 4 h dark-recovery were significantly less in mi(vit)/mi(vit) mutants compared with controls. Immunohistochemical detection of IRBP indicated an altered distribution of the protein in the mutant mice compared with controls. There was accumulation in the region of the inner segments in mutant retinas rather than distribution only to the RPE/OS apical regions as in controls. The data suggest that regeneration of rhodopsin is reduced by 4 weeks postnatally in the mi(vit)/mi(vit) mouse. There is partial detachment of the retina at this age; and IRBP, thought to be essential for proper functioning of the visual cycle, is aberrantly distributed in this mutant.

Animals↗
PubMed1997

Stunting syndrome in broilers: effect of glucose or maltose supplementation on digestive organs, intestinal disaccharidases, and some blood metabolites.

The effect of supplementing a cornsoybean diet (C) with glucose (G) or maltose (M) on young broilers (from hatch to 3 wk of age) affected by stunting syndrome (SS) was studied. Stunting syndrome was induced by orally administering an inoculum prepared from the intestines of SS broiler chicks. Relative to the M diet, the G diet improved growth and feed utilization and increased feed intake in naive (NA) control chickens. The C diet was intermediate in this respect. In contrast to the NA chickens, diet did not affect growth or feed utilization in SS chicks. Changes in the relative weights of the gastrointestinal tract segments were evident by 1 wk of age and hypertrophy of these segments persevered to 3 wk of age. Stunting syndrome infection was accompanied by a significant increase in pancreatic trypsin-specific activity during Weeks 1 and 2, and in chymotrypsin activity at 1 wk. During this time, amylase-specific activity was not affected. At 3 wk of age, the specific activities of amylase, trypsin, and chymotrypsin in the pancreas were lower in the inoculated vs control birds. Whereas no significant effect of SS was observed with activities of amylase in the intestinal contents, trypsin activity was higher in SS chicks at 1 wk, and that of chymotrypsin lower during Weeks 2 and 3. Relative to NA chicks, the maltase and saccharase activities of SS chicks were much lower during Week 1, but increased later on and were similar to NA chick values at 2 and 3 wk. Whereas the level of blood plasma proteins did not vary from 1 to 3 wk in the NA chicks, it increased gradually in SS chicks to a level that significantly exceeded that in their NA counterparts. Blood plasma glucose and triglyceride levels were slightly lower in the SS chicks (NS), and the blood plasma cholesterol level was significantly reduced during Week 2. Relative to NA chicks, SS infection caused a significant increase in plasma calcium during Weeks 2 and 3, accompanied by a significant reduction in blood plasma phosphorus at 2 wk only. No difference was observed in the blood plasma level of uric acid, which peaked in both treatments during Week 2, or in D-beta-hydroxybutyric acid level, which was quite stable during the experimental period. Stunting syndrome infection was accompanied by a dramatic increase in amylase and alkaline phosphatase activities in the blood plasma, and by a slight but significant decrease in activity of lactic dehydrogenase. Stunting syndrome was concluded to be an affliction not only of digestion but also of metabolism. The main depression in growth caused by SS inoculation is probably due to metabolic alterations beyond those of digestion and absorption.

Aging↗
PubMed1997

Responses of meat-type chickens to choice feeding of diets differing in protein and energy from hatch to market weight.

Chickens from three genetic stocks known to differ in growth potential consumed ad libitum either a single (control) diet or a choice of two diets that differed in protein and energy. Formulation of the choice diets was such that when mixed in specific proportions they provided single diets that decreased in protein and increased in energy over the experimental period. When comparisons of feeding regimens were made at a common age, body weights and feed efficiencies for all stocks were enhanced in chicks fed a single diet. When comparisons were made at a common body weight for controls, chickens fed the single diet were about 15% heavier than those given a dietary choice. For feed efficiency, however, the pattern remained for the faster growing stock whereas there was no difference between feeding regimens for the slower growing stock. Chicks provided a choice of diets had heavier abdominal fat pads and lighter breasts relative to body weight than those fed a single diet. With choice feeding, there were stock by diet interactions for dietary preferences through the first 9 d after hatch. Early on, the interactions resulted from the faster growing stocks exhibiting a greater preference for the diet higher in protein and lower in energy than the slower growing stock. By Day 5, however, the interaction occurred because stocks exhibited either no dietary preference or preferred the diet that was lower in protein and higher in energy. Regardless of genetic stock, at 9 d of age and thereafter there was a clear preference for the diet lower in protein and higher in energy than the diet higher in protein and lower in energy. These data for feed intake were consistent with behavioral observations that showed a preponderance of chicks eating from the feeder containing the diet lower in protein and higher in energy. Compared to a single diet, under choice feeding, energy utilization was negatively influenced more in the faster than slower growing stocks. Protein and sulfur amino acid utilization was not affected by feeding regimen in faster growing stocks, but was enhanced under choice feeding in the slower growing stock. Although lysine utilization was enhanced by choice feeding in all stocks, the effect was greater in the slower than in the faster growing ones. These data demonstrate that although broiler diets are formulated to enhance growth and overall feed efficiency, chicks that are provided a dietary choice of protein and energy do not eat to maximize growth or feed efficiency.

Aging↗
PubMed1997

Pyloric exclusion in the management of duodenal trauma: is concomitant gastrojejunostomy necessary?

Pyloric exclusion with gastrojejunostomy (PE-GJ) has been recommended in patients with severe injuries to the pancreatoduodenal complex. Recently, the management philosophy for pancreatoduodenal injuries has been that less treatment is probably the best treatment. But whether gastrojejunostomy (GJ) should be used routinely with pyloric exclusion (PE) remains controversial. A retrospective review was conducted of patients who underwent PE at a Level I trauma center during a 36-month period. Forty-five patients had duodenal injuries and 12 of these (27%) underwent PE for management of complex duodenal injuries. Gunshot wounds were the cause of the injuries in 10 of the 12 patients (83%). Eight patients (67%) underwent PE-GJ and had a mean hospital stay of 25 days. Four patients (33%) underwent PE alone and had a mean hospital stay of 29 days. All 12 patients had spontaneous opening of the PE, regardless of the technique used. One patient (12.5%) in the PE-GJ group developed marginal ulceration and significant hemorrhage, and one patient died in the PE-GJ group. The reported incidence of marginal ulceration in the PE-GJ group, the spontaneous opening of the pylorus, and the need to limit the extent of surgical repair to focus on all other associated lesions present in these patients, suggest that GJ should not be used routinely in patients undergoing PE for the management of severe pancreatoduodenal injuries.

Adult↗
PubMed1996

A simple device for closure of fasciotomy wounds.

Early decompressive fasciotomy is essential in the prevention of the sequelae of compartment syndrome. Many techniques have been described for the closure of the fasciotomy wound, and controversy exists as to which method is the best. Primary closure is often impossible secondary to tissue retraction and edema. Split-thickness skin grafting leaves a thin, insensate, and often aesthetically unpleasing result. Gradual mechanical dermal apposition has been used with increasing frequency, and has been shown to be effective in the closure of fasciotomies, but often takes 7-10 days for closure. We present our experience with the STAR, a mechanical method of fasciotomy wound closure that is effective in 2-4 days, and is extremely simple to use.

Adolescent↗
PubMed1996

Comparative development of digestive organs, intestinal disaccharidases and some blood metabolites in broiler and layer-type chicks after hatching.

1. Body weight, digestive organ weights, and activities of disaccharidases (maltase and saccharase) activities were determined from day of hatch to 21 d of age in meat- and egg-type chickens. Blood plasma was analysed for enzyme activities and metabolite concentration. 2. In meat-type chickens food intake and growth rate were about 3-fold those in egg-type chickens. Food efficiency was superior in meat-type chickens throughout the experimental period. 3. Meat-type chickens hatched with disaccharidase activities exceeding those found in their egg-type counterparts 2- to 5-fold. From 7 d of age on, this trend reversed, i.e. activity was much higher in egg-type than in meat-type chickens. 4. Blood plasma amylase activity increased gradually in meat-type chickens and was higher than in egg-type chickens to 14 d of age. No breed differences were observed for alkaline phosphatase or lactate dehydrogenase activities during the experimental period. 5. Blood plasma concentrations of total protein, albumin, glucose, and calcium, were lower in meat than in egg-type chickens.

3-Hydroxybutyric Acid↗
PubMed1996

Immunoresponsiveness of fast-growing chickens as influenced by feeding regimen.

1. Immunoresponsiveness and disease resistance were measured in broiler males maintained on ad libitum feeding throughout or on alternate-day feeding. Alternate-day restrictions were started 1 and 2 d after hatch so that on any one day there were chicks fed and fasted. 2. Severity of response to E. coli challenge as measured by lesion scores, and mortality was greater for chicks fed ad libitum than those fed on alternate days. For chicks fed on alternate days, lesion scores were lower for those without access to feed for the 24-h period immediately after challenge. 3. Spleen weights, the indicator of response to marble spleen disease virus challenge, were higher for chicks fed ad libitum than those fed on alternate days. 4. Antibody response to sheep red blood cell antigen was not affected by feeding regimen. 5. Ratios of heterophils to lymphocytes were higher for chicks given access to feed for the previous 24-h period than for those fasted during the previous 24-h or those that had been fed ad libitum. 6. Results of this experiment suggest that for alternate-day feeding programs, vaccination be administered on the day that chicks are not fed.

Animals↗