Biomedical subjects

S L Branton

Publications and source records attributed to S L Branton.

At least 37 records · Page 2Linked to original sources

PubMed2004

Threonine needs of broiler chickens with different growth rates.

The Thr needs in 3 commercial broiler strains (A, multipurpose; B, high yield; C, high yield) known to differ in terms of feed intake, growth rate, and breast yield were evaluated. Birds were randomized across 96 floor pens (12 birds/pen), received a common diet from d 1 to 20, and were fed graduations of Thr (0.52 to 0.87% total Thr in 0.07% increments) from d 21 to 42. Treatments (3 x 6 factorial) were replicated 5 or 6 times. The corn, soybean meal, and peanut meal test diet contained 0.43 and 0.96% digestible Thr and Lys, respectively. An additional group of strain C birds (6 pens) was maintained on a corn-soybean meal diet containing surfeit Thr (0.73% of diet). Birds fed the corn and soybean meal diet performed similarly (P < or = 0.05) to birds fed peanut meal diets. A feed conversion interaction (P < or = 0.05) occurred indicating that strain C was more sensitive to Thr deficiency than strains A and B. The abdominal fat interaction (P < or = 0.05) indicated that strain A had more relative abdominal fat than strains B and C. All strains differed (P < or = 0.05) in terms of BW gain (A, 78.2; B, 75.1; C, 72.9 g/d). Strain C had the lowest (P < or = 0.05) feed intake, which resulted in the lowest (P < 0.05) Thr intake, but it had the highest (P < or = 0.05) breast meat yield. Most parameters tested yielded quadratic (P < or = 0.05) models whereby Thr estimates could be predicted. Namely, BW gain and breast meat yield resulted in total Thr estimates (95% of maximum response) of 0.74 and 0.71%, respectively, which are in close agreement with the 1994 NRC (0.74%). The plasma Thr sigmoid response verified the former estimates. Analysis of strain intercepts and slopes as affected by Thr differed (P < or = 0.05) in terms of feed intake but not BW gain or breast meat yield. The 21 to 42 d Thr need across strains was estimated as 0.74% total or 0.65% digestible. Because dietary Lys was not in excess of the bird's needs, the former digestibility estimate equated to a Thr/Lys of 0.68.

Abdomen↗

PubMed2003

Total and water-soluble phosphorus in broiler litter over three flocks with alum litter treatment and dietary inclusion of high available phosphorus corn and phytase supplementation.

Three pen trials were conducted to determine the main effect of alum addition to litter on form of poultry litter P using a 2 x 2 factorial structure of the subunit treatments: diets including high available phosphorus/low phytate corn (HAPC) and phytase (PHYT). Male broilers (1,760 per flock) were grown to 42 d having starter diets with 0.45% available P and grower diets with 0.35% available P. In the first trial, total litter P (tP) was greatest for the yellow dent corn (YDC) diet (12 g/kg) and least for the HAPC and PHYT combination (H&P) diet (6.9 g/kg) with the individual PHYT and HAPC diets falling in between at 9.1 g/kg and 9.4 g/kg tP. Also in the first trial, the litter water-soluble P (wP) was highest for PHYT (2.8 g/kg), least for the HAPC and H&P diets (1.5 g/kg) with the YDC diet falling between (2.2 g/kg). Alum was added to the litter after the first experiment. In the second and third experiments, alum inclusion significantly reduced the wP when compared with the treatments with no alum. In the third trial, the least wP was present in the alum-HAPC treatment. Phytase, YDC, and HAPC diets with no alum litter treatment generated the most wP. Since these diets appear to have little or no difference with respect to quantity of wP, this work suggests that form of litter P generated by alternative diets should be considered as criteria when attempting to reduce P in broiler litter applied to land.

6-Phytase↗

PubMed2003

Effects of F-strain Mycoplasma gallisepticum inoculation on serum very low density lipoprotein diameter and fractionation of cholesterol among lipoproteins in commercial egg-laying hens.

Experimental inoculation with the F-strain of Mycoplasma gallisepticum (FMG) at 12 wk of age has been shown to affect the performance, liver, reproductive organs, and yolk lipid characteristics of commercial layers. Therefore, this study was conducted to determine the serum lipoprotein characteristics of commercial egg-laying hens at 16 wk of age and throughout lay after inoculation with FMG at 12 wk of age. Mean diameters of very low density lipoproteins (VLDL) were determined for the 10th, 50th, and 90th percentiles of serum total VLDL of each hen. Percentages of total serum cholesterol recovered in VLDL and low and high density lipoprotein particle classes were also determined. Inoculation of birds with FMG at 12 wk did not change the physical properties or relative concentrations of their circulating lipoproteins. However, the age of the bird had significant differential effects on all the parameters examined. These data demonstrate that FMG-inoculation at 12 wk of age does not affect the lipoproteins of laying hens, but because these birds were housed in biological isolation units, these results do not preclude the possibility that these yolk precursors may be affected in FMG-infected birds that are housed in facilities in which there are increased levels of environmental stress. These data further suggest that alterations in liver, reproductive organs, and yolk lipid characteristics in response to FMG, as noted in previous reports on commercial layers, are not mediated through changes in circulating VLDL diameters.

Animals↗

PubMed2003

Effects of F-strain Mycoplasma gallisepticum inoculation at twelve weeks of age on egg yolk composition in commercial egg laying hens.

In two trials, the effects of F-strain Mycoplasma gallisepticum (FMG) on the contents of egg yolks from commercial Single Comb White Leghorn laying hens were investigated over a production cycle. Ten hens were assigned to each of 8 (trial 1) or 16 (trial 2) negative pressure fiberglass biological isolation units. Birds in half of the total units served as sham-inoculated controls, and those in the other half were inoculated with FMG at 12 wk of age. Eggs were collected and yolks were harvested at various times during the prepeak, peak, and postpeak periods of both trials for constituent analysis. Yolk constituents analyzed in these trials included moisture, total lipids, cholesterol, triglycerides, phospholipids, and fatty acids. In both trials, total yolk lipid at 22 wk of age was significantly decreased in birds inoculated with FMG. In trial 1, yolk cholesterol at 28 wk was significantly decreased in FMG-inoculated birds. Yolk linoleic acid in trial 1 and yolk stearic and arachidonic acids in trial 2 were significantly increased in FMG-inoculated birds compared to FMG-free birds. In trial 2, yolk myristic, palmitoleic, and oleic acid percentages were significantly decreased in FMG-inoculated birds compared to FMG-free birds. These data suggest that alterations in egg production in commercial layers in response to an FMG infection at 12 wk of age are associated with changes in yolk composition.

Aging↗

PubMed2003

Influences of supplemental dietary poultry fat and F-strain Mycoplasma gallisepticum infection on the early performance of commercial egg laying hens.

F-strain Mycoplasma gallisepticum (FMG) may alter reproductive performance in layers through its effects on lipid metabolism. Therefore, the influences of 1.5% supplemental dietary poultry fat (PF) and FMG infection on the early performance of commercial egg-laying hens were determined. Birds were either sham- or FMG-inoculated at 12 wk, and experimental diets were initiated at 20 wk of age. Body weight at 12, 20, and 24 wk, total daily egg mass, feed consumption and feed conversion at 20 and 24 wk, weekly egg weight between 19 and 26 wk, weekly egg production (EP) between 18 and 26 wk, and weekly mortality between 12 and 26 wk of age were determined. Inoculation with FMG reduced EP at 18 and 19 wk of age. Between 20 and 26 wk, FMG reduced EP in birds fed control diets, conversely, PF eliminated differences in EP between sham- and FMG-inoculated birds. Furthermore, at wk 20 and 24, birds consumed less feed when fed PF-supplemented diets than when fed control diets if they were sham-inoculated, but the difference in feed consumption between diets was ameliorated if birds were previously inoculated with FMG. These data demonstrate that the effects of a 12-wk inoculation of FMG on EP and feed consumption through 26 wk of age in commercial egg-laying chickens can be modified by 1.5% supplemental dietary P F. More specifically, PF may alleviate reductions in early EP due to FMG.

Aging↗

PubMed2003

Effects of F-strain Mycoplasma gallisepticum inoculation at twelve weeks of age on the blood characteristics of commercial egg laying hens.

In two trials, the effects of an F-strain Mycoplasma gallisepticum (FMG) inoculation at 12 wk of age on the blood characteristics of commercial Single Combed White Leghorn laying hens were investigated throughout lay. Variables measured in both trials were whole blood hematocrit, plasma protein (PP), and serum cholesterol, triglycerides (ST), and calcium. In both trials, hematocrit at 20 wk of age was significantly increased in birds inoculated with FMG. In trial 1, ST and PP were significantly increased at 22 wk of age by FMG, while ST and PP were significantly decreased in FMG-inoculated birds at wk 54 and 52, respectively. When combined with the establishment of an FMG infection, the initial weeks of egg production become particularly stressful to the bird. Increases in these independent blood parameters between 8 and 10 wk postchallenge are suggestive of compensatory responses in these birds to an FMG challenge. Postpeak decreases in both ST (54 wk) and PP (52 wk) in FMG-infected birds may be the result of a more chronic effect of FMG on lipid and protein synthesis in the liver. These data are the first to suggest that alterations in egg production in response to FMG-infection in commercial layers, as noted in a previous report, may be associated with changes in hematocrit. However, because ST and PP were not affected by FMG in both trials, the responses of these blood parameters to FMG-infection may be inconsistent among flocks.

Animals↗

PubMed2002

Effects of F-strain Mycoplasma gallisepticum inoculation at twelve weeks of age on performance and egg characteristics of commercial egg-laying hens.

The effects of F-strain Mycoplasma gallisepticum (FMG) inoculation during the pullet period on the subsequent performance and egg characteristics of commercial Single Combed White Leghorn hens were evaluated. In two trials, BW, feed consumption, egg production (EP), egg weight, egg size class, relative eggshell water vapor conductance, and relative percentages of eggshell, yolk and albumen weights were determined through approximately 60 wk of age. In each trial, pullets at 12 wk of age were randomly assigned to negative pressure biological isolation units. Birds in one-half of the total units were inoculated with FMG, and the other half were sham-inoculated with sterile media. In both trials, onset of lay was delayed approximately 1 wk in layers inoculated with FMG. Control birds that had not been previously inoculated with FMG laid their first egg at 18 wk of age, while birds that had been previously inoculated with FMG laid their first egg at 19 wk of age. In Trial 1, FMG-inoculated hens laid significantly fewer total eggs, which became apparent at each week after Week 42. In Trial 2, a numerical decrease in total EP occurred, and the percentage of undersized eggs laid by FMG-inoculated birds was significantly lower at 19 wk of age but was higher at 20 and 21 wk when compared to controls. Mortality was not significantly different between the treatments in either trial. These data demonstrate that when birds are housed in isolation facilities and inoculated with FMG at 12 wk of age, onset of lay is delayed. These data also suggest that FMG may lead to delays in undersize EP and decreases in total EP. However, because significant FMG effects on these parameters were observed in only one trial, additional studies may be necessary to verify these effects.

Aging↗

PubMed2002

Effects of F-strain Mycoplasma gallisepticum inoculation at twelve weeks of age on digestive and reproductive organ characteristics of commercial egg laying hens.

Experimental inoculation with the F-strain of Mycoplasma gallisepticum (FMG) between 8 and 18 wk of age is known to affect reproductive performance in commercial layers. Therefore, two trials were conducted to determine if changes in digestive and reproductive organ characteristics also occur in commercial laying hens infected with FMG at 12 wk of age. In Trial 1, liver weight, liver lipid and moisture contents, ovary weight, ovarian follicular hierarchy, and the weights, lengths, and histologies of the infundibulum, magnum, isthmus, uterus, and vagina were determined. In Trial 2, fatty liver hemorrhagic syndrome (FLHS) incidence and the weights, lengths, and histologies of the duodenum, jejunum, and ileum were determined in addition to the parameters examined in Trial 1. In both trials, the average number of mature (diameter > or = 12 mm) ovarian follicles was lower in FMG-inoculated hens in comparison to controls. Also, magnum/oviduct (cm/cm) length was reduced in treated birds. In Trial 2, isthmus/BW and isthmus/oviduct (g/ g) weight were decreased at 46 wk of age, and vagina/ BW and vagina/oviduct (g/g) weight were decreased at both 20 and 36 wk of age due to FMG treatment. In Trial 2, FMG treatment resulted in a 50% increase in the number of FLHS birds. Furthermore, treatment caused a decrease at 20 wk of age and an increase at 44 wk of age in liver moisture content. However, the intestinal characteristics examined were not affected by FMG inoculation. Altered liver, ovarian, and reproductive organ characteristics were associated with FMG infection in commercial layers. More specifically, FMG inoculation at 12 wk resulted in a higher incidence of FLHS, ovarian follicular regression, and decreased isthmal and vaginal proportions of the reproductive tract. These data clearly demonstrate that alterations in performance and egg characteristics of layers inoculated with FMG at 12 wk of age are related to mutual functional disturbances in the liver, ovary, and oviduct without concomitant intestinal changes.

Aging↗

PubMed2001

The effect of nipple height on broiler performance.

Two trials, using a total of 3,200 male broilers, were conducted to compare the effects of a trough drinker versus three different heights on a nipple drinker system on body weight gain and feed:gain. The broilers were housed in temperature-controlled litter pens at 25 or 30 C. An 8-ft open trough was used. The nipple drinker heights were adjusted as 1) low (no neck stretch and drink from the side of the beak), 2) medium (stretch neck and drink from the end of the beak), and 3) high (first elevate breast, then stretch neck and drink from the end of the beak) positions. The nipple heights were adjusted twice weekly by visual inspection. The open drinker produced the heaviest birds. No significant treatment differences were observed for feed:gain at 25 C but increased numerically with increasing nipple height. This same pattern was evident at 30 C, but statistically significant differences did occur. Drinking from a nipple drinker is an unnatural drinking act for birds, and the greater the neck extension, especially during a panting situation, the more detrimental the effect on both body weight and feed:gain.

Animal Feed↗

PubMed1997

The effect of added complex carbohydrates or added dietary fiber on necrotic enteritis lesions in broiler chickens.

Two trials utilizing two corn diets and four wheat diets were conducted. In Trial 2, all chicks were crop-infused at 9 d of age with Eimeria acervulina. In both trials, a broth culture of Clostridium perfringens was mixed with the diets for 3 consecutive d. Necrotic enteritis lesion scores were lowest in chickens consuming the corn diet with no C. perfringens and highest in chickens fed the wheat diets with C. perfringens. Chickens consuming a wheat diet with no added complex carbohydrates or added fiber exhibited the highest lesion score. Chickens on wheat diets with 4% new, ground, pine shavings had intestinal lesion scores intermediate to those of chickens that consumed the wheat or corn diets. Chickens consuming corn diets yielded the lowest lesion scores. Chickens provided diets containing either guar gum or pectin were not fully consumed and thus probably reduced the number of challenge organisms ingested.

Animals↗

PubMed1996

The effects of nonautoclaved and autoclaved water-soluble wheat extracts on the growth of Clostridium perfringens.

Clostridium perfringens is the causative agent of necrotic enteritis, a commonly diagnosed disease in chickens that is also observed in turkeys and geese. Two trials were conducted to determine the in vitro effect of filter-sterilized, water-soluble wheat extracts on the growth of C. perfringens. The extracts were either nonautoclaved or autoclaved at 121 C for 40 min and were used to reconstitute thioglycolate broth media. Results of this study suggest that growth of C. perfringens is suppressed in vitro by inclusion of either extract. Glycosyl composition analysis revealed no significant differences in arabinose, xylose, or mannose content between the nonautoclaved and autoclaved extracts. Galactose, glucose, and total glycosyl content were significantly higher in the nonautoclaved extract.

Animals↗

PubMed1996

The effect of brooding temperature on broiler performance.

In response to the energy crisis of the 1970s, this laboratory recommended that initial brooding temperatures for broilers be reduced to 29.4 C from 32.2 or 35 C. Because environmental temperature has been implicated in the ascites syndrome, this work was conducted to see whether the recommended brooding temperature of 29.4 C the 1st wk, 26.7 C the 2nd wk, and 23.9 C the 3rd wk would be satisfactory for broiler production when compared with higher brooding temperature regimens starting at 32.2 or 35 C. Brooding chicks at a temperature of 29.4 C the 1st wk, 26.7 C the 2nd wk, and 23.9 C the 3rd wk did not adversely affect broiler performance at 6 wk of age, when compared with higher brooding temperature regimens. Under the conditions of this experiment, brooding chicks at a temperature of 29.4 C the 1st wk, 26.7 C the 2nd wk, and 23.9 C the 3rd wk was satisfactory when compared with the higher temperature brooding regimens. Mortality due to ascites and total mortality significantly increased for broilers brooded in the negative control temperature regimen of 26.7 C the 1st wk, 23.9 C the 2nd wk, and 21.1 C when compared with some or all of the higher brooding temperature regimens. Heat loss calculations based on a commercial setting show an 18% savings in liquified petroleum (LP) gas usage for chicks brooded at 29.4 vs 35 C and a savings of 10% in LP gas usage for chicks brooded at 29.4 vs 32.2 C on a winter day.

Aging↗

PubMed1991

Research note: Mycoplasma gallisepticum isolations resulting from dry versus wet swabs.

Commercial Leghorns vaccinated with F strain Mycoplasma gallisepticum were used to determine the effect of hydration of swab material with Frey's broth media on M. gallisepticum isolation. Twenty-four hens from each of four 10,000 bird houses were randomly selected and swabbed from the choanal cleft region. Twelve birds from each house were swabbed with ethylene-oxide-sterilized, 2.4-mm diameter rayon-tipped swabs, and 12 hens were swabbed with the same type swabs wetted with sterile Frey's broth media. Results of the present study demonstrate that wetting of the swab prior to swabbing does not affect the recovery of M. gallisepticum from commercial layers.

Animals↗

PubMed1990

A comparison of flow cytometry and other techniques used for diagnosing Mycoplasma infections.

Mycoplasma isolates from chickens are usually identified by a fluorescent antibody (FA) technique that requires 7 to 10 days from sampling to the completion of identification. The FA procedure uses Mycoplasma-positive antibodies conjugated with fluoroisothiocyanate (FITC) to identify the colonies of the organism on agar. This paper describes a flow cytometric procedure that uses the same antibody-FITC conjugate and can be completed in 3 or 4 days. Broilers and egg-type hens inoculated with Mycoplasma gallisepticum and M. synoviae were swabbed from the choanal cleft and cultures were grown in broth. Broth aliquots were briefly incubated with polyclonal antisera to M. gallisepticum and M. synoviae conjugated with FITC, the same reagents routinely used in the FA technique. The sample was then analyzed by flow cytometry for the association of the fluorescent label and the organism. Samples from inoculated chickens incubated with the homologous antibody-FITC had greater fluorescent intensity than did those incubated with the heterologous antibody-FITC. Diagnosis by flow cytometry was consistent with that by the FA technique except that in one trial one sample was incorrectly identified by flow cytometry as positive for M. gallisepticum, although it was not inoculated with M. gallisepticum. Also, flow cytometry did not correctly identify M. synoviae organisms as readily when broilers were inoculated with both M. gallisepticum and M. synoviae.

Agglutination Tests↗

PubMed1988

Effect of environmental temperature and feeding regimen on quantity of digestive tract contents of broilers.

Carcass contamination from contents of the digestive tract during processing is a recurring problem for the broiler industry. Environment and feeding regimen are often implicated as causative factors. The effects of environmental temperature and meal feeding on passage of feed through the digestive tract of broilers were examined. Broilers were reared in environmental chambers in five experiments. In the first experiment, environmental temperatures were constant temperatures of 16 and 27 C and cycles of 16-24-16 and 24-35-24 C and rate of passage of feed through the digestive tract (ROP) was determined with ferric oxide. Temperature did not consistently affect ROP. In the other four experiments, various environmental temperatures were investigated and broilers were fed continuously or for 12 or 16 h/day. Contents of the crop, proventriculus plus gizzard, and small intestine were weighed 2, 4, 6, and 8 h after feeding withdrawal. Environmental temperature did not directly affect the movement of digesta but the feeding regimen affected the quantity of digesta in some segments of the tract. Environmental temperature may have indirectly affected the quantity of feed in the crop by affecting the quantity of feed consumed. Limiting the feeding period resulted in retention of digesta in the crop of some broilers for an extended period. This increased the variability in quantity of crop contents. A feeding regimen X temperature interaction resulted in increased small intestine weight for meal-fed broilers at 16 C.

Animals↗

PubMed1988

Position of Meckel's diverticulum in broiler-type chickens.

In each of three trials broiler-type chickens were used to determine whether Meckel's diverticulum resides in a constant position along the intestinal tract. Chickens were provided a basal diet ad libitum through 49 (Trials 2 and 3) or 52 days of age (Trial 1). Body weight and total intestine length as well as the lengths of the intestine from the gizzard to Meckel's diverticulum (GMD) and from Meckel's diverticulum (MD) to the cecal openings (MDC) were then recorded. When intestine length was expressed as a percentage of body weight, significant differences were noted between sexes. However, no significant differences were observed between sexes for either GMD or MDC relative to total intestinal length. Results of this study indicate that MD resides in a constant position along the length of the intestinal tract. This constancy of position supports the use of MD as a boundary point of the intestine.

Animals↗

PubMed1987

Body temperature of acclimated broilers during exposure to high temperature.

Short-term acclimation to high temperatures increased resistance of broilers to heat exposure. Two trials were conducted to determined the effect of acclimation on body temperature (Tb) during heat exposure. Broilers, 46-days old, were maintained at control or acclimating temperatures for 4 days. The control temperature was a constant 21 C with a 10 C dewpoint, and the acclimating temperature was a diurnal cycle of 24-35-24 C with a constant 21 C dewpoint. During the 4th day, broilers of both groups were exposed to temperatures of 41 C and 23 C dewpoint for 210 min. Body temperature was determined at the beginning of the heat exposure and at 30-min intervals until the end of the exposure. The Tb of both groups increased throughout heat exposure, but acclimated broilers had significantly lower Tb than control broilers from 90 through 210 min. Acclimated broilers had significantly lower heat stress mortality. The data show that acclimated broiler's Tb rises upon exposure to heat but that acclimation gives the capacity to stabilize Tb above normal Tb. The data also suggest Tb is preferable to mortality as a measure of acclimation in broilers.

Acclimatization↗

PubMed1987

Influence of a wheat diet on mortality of broiler chickens associated with necrotic enteritis.

In an experiment to determine methods of incorporating soft winter wheat into broiler diets, a significant increase in mortality was observed in broilers fed wheat in crumbled diets. This increase in mortality was associated with necrotic enteritis with Clostridium perfringens indicated as the causative pathogen and complicated by a coccidiosis outbreak. When yellow corn was used in the diet, mortality was 2.9%. Use of all wheat, ground with a hammer mill, increased mortality to 28.9%. However, roller mill-ground wheat diet resulted in a mortality of 18.1%. When the grain component was approximately 50% wheat and 50% corn, mortality was 12.6% for broilers fed hammer mill-ground wheat and 3.4% for roller mill-ground wheat. Grain and feed were tested for several mycotoxins. Low levels of deoxynivalenol were found in both corn and wheat diets, but no differences between the corn and wheat-based diets were found that would explain the incidence of enteritis.

Animal Feed↗