Biomedical subjects

G F Barbato

Publications and source records attributed to G F Barbato.

At least 19 recordsLinked to original sources

PubMed2002

Correlated responses in body composition to divergent selection for exponential growth rate to 14 or 42 days of age in chickens.

Chicks divergently selected for 14-d (14H and 14L) or 42-d (42H and 42L) exponential growth rate (EGR) over five generations were used to determine correlated responses between growth at different ages and body composition. Regression coefficient estimates across five generations of selection were not significant for any line at either age for percentage total body water or protein. Genetic correlations between EGR from hatching to 14 d of age (EGR14) and 42-d percentage carcass fat were -0.18, -0.57, 0.63, and -0.79 among the 14H, 14L, 42H, and 42L lines, respectively. Genetic correlations between EGR from hatching to 42 d of age (EGR42) and 42-d percentage carcass fat were 0.09, -0.67,0.50, and -0.75 among the 14H, 14L, 42H, and 42L lines, respectively. During the short-term selection experiment, selection for fast EGR14 or EGR42 increased fat at the age of selection. However, selection for fast EGR42 increased body weight and percentage fat at 42 d of age (DOA), whereas selection for fast EGR14 increased body weight but not fat at 42 DOA. Therefore, it is possible to simultaneously select for high body weight at, or near, the inflection point of the growth curve without increasing fat deposition or obesity by taking advantage of the lack of a genetic correlation between EGR14 and body fat percentage at later ages.

Aging↗

PubMed2001

Identification of norepinephrine in bovine oviductal fluid by high performance liquid chromatography.

The final stages of sperm maturation, fertilization and early embryonic development take place in the microenvironment of the oviduct and are essential for successful reproduction in mammals. Although catecholamines have been shown to have beneficial effects on mammalian gametes in vitro, identification of catecholamines in native bovine oviductal fluid has not been studied. The objective of this research was to identify catecholamines in bovine oviductal fluid and to determine whether concentrations of catecholamines change with stage of the estrous cycle. Oviductal fluid was collected via indwelling oviductal cannulae and assayed for the presence of catecholamines by high performance liquid chromatography. Norepinephrine was the only catecholamine detected, in concentrations ranging from 0.828 ng/ml - 1117 ng/ml. The presence of norepinephrine in oviductal fluid corresponded to a period of time just prior to, during, and after ovulation, when serum progesterone levels were low. This was a consistent finding in ODF collected from normally cycling cows. Potential functions of norepinephrine in oviductal fluid include regulation of fluid formation, induction of capacitation and the acrosome reaction in spermatozoa, and cleavage of the early embryo.

Animals↗

PubMed2001

2. the effect of feeding excess methionine on live performance, carcass traits, and ascitic mortality.

Appetite suppressant activity of dietary excess Met was investigated in a 7-wk trial for the potential to restrict feed intake and the early growth of broilers as a means of reducing the incidence of ascitic mortality. A basal starter diet meeting the minimum NRC (1994) requirements for broilers was compared with a diet providing Met above the requirement (1.86% of the diet). Excess dietary Met was fed to the broilers from 4 to 11 d. Grower and finisher diets were provided from 22 to 35 d and from 36 to 49 d. Birds in two rooms were exposed to cool temperatures to induce ascites. The temperature program for the cool rooms was as follows: 12 h at 24 C daily (0800 to 2000) and 12 h at 15 C nightly (2000 to 0800) from 14 to 49 d, whereas the other two rooms were maintained at 24 C (control rooms). Body weight gain was depressed by 20.4% when excess Met was fed from 4 to 11 d. Feed conversion was also negatively affected by the excess dietary Met. A brief recovery was achieved from 11 to 14 d upon refeeding the well-balanced basal starter diet. Full compensatory growth was achieved by 49 d when body weight was equal to that of birds fed the basal diet. Excess dietary Met did not affect the carcass traits with the exception of abdominal fat pad, which was reduced by the excess dietary Met in the control rooms, whereas the opposite was true in the cool rooms. Ascitic mortality was not altered by dietary Met, however, the total mortality was significantly reduced by excess Met in the control rooms.

Animal Nutritional Physiological Phenomena↗

PubMed2001

1. Appetite suppressant activity of supplemental dietary amino acids and subsequent compensatory growth of broilers.

This study was conducted to take advantage of the appetite-suppressant effect of excessive dietary amino acids in reducing feed intake and, in turn, restricting the early rapid growth of broilers to minimize metabolic disorders. Dietary amino acids were supplemented to a basal diet to yield a total of 1.57, 2.57, and 3.57% His; 2.7, 4.3, and 5.9% Lys; 1.36, 2.16, and 2.96% Met; 2.8, 3.8, and 4.8% Thr; and 1.27, 2.27, and 3.27% Trp and were fed to 408 chicks from 4 to 11 d of age. Fifteen dietary treatments of His, Lys, Met, Thr, and Trp were compared to the basal diet. Feed consumption was measured daily. Body weight measurements were taken at 0, 4, 7, 11, 14, and 21 d. At 21 d, pectoralis major and minor muscles, liver, and abdominal fat pad were weighed. High levels of Met and His caused the greatest depression in appetite from 4 to 11 d, and Thr, Trp, and Lys were found to be less potent. The exponential growth rate (EGR) of birds from 4 to 11 d of age was significantly reduced by the intermediate and high levels of the amino acid supplementation. From 11 to 14 d, EGR was greatest with high levels of Met or Trp, indicating more potential compensatory growth realized with these treatments. The high level of His decreased the percentage of pectoralis minor muscle yield, whereas the high level of Lys and Met increased the percentage of liver compared to those fed the basal diet. These results indicate that it is possible to use excessive individual amino acids in diets to suppress the appetite and early rapid growth to alleviate or minimize metabolic disorders.

Abdomen↗

PubMed1999

Genetic relationships between selection for growth and reproductive effectiveness.

The domestic and international poultry industries have gone through many changes over the last 50 yr. One constant in the meat-type poultry industry has been the emphasis on genetic improvement of growth. Using lines from a double, divergent selection experiment, data are presented on the genetic relationships between growth to different ages and reproductive parameters. During the last three generations of selection an in vitro sperm binding assay was used and evaluated for its usefulness in a selection program for growth-related phenotypes. Growth to different ages can have markedly different genetic architecture, compared to evaluating body weight at a fixed age. Growth is a nonlinear phenomenon and should be evaluated as such within the context of a genetics program. Fertility is positively correlated with growth to 14 d of age (EGR14), but negatively correlated with growth to 42 d of age (EGR42). This difference is primarily due to the high, negative correlation between exponential growth from 14 to 42 d of age (EGR14/42) and reproductive phenotypes. Roosters were also evaluated with an in vitro sperm binding assay, which is highly correlated with fertility. The genetic architecture of the sperm binding assay was very similar to that of fertility, with an additive genetic correlation of 0.75. Further, it was shown that culling the worst 25% roosters on the basis of the sperm binding assay would have very little effect on the growth performance of the resulting progeny, yet increased the number of chicks produced per rooster by 10 to 25% (depending upon the population).

Animal Husbandry↗

PubMed1998

Distribution and clearance of cocaine in brain is influenced by genetics.

The purpose of this study was to examine the pharmacokinetics of cocaine in two inbred mouse strains, C57BL/6 (B6) and DBA/2 (D2). Male and female mice were administered 30 mg kg(-1) cocaine IP and killed after 5, 15, 30, or 60 minutes postinjection. Brains were removed quickly and assayed for total brain cocaine concentration. Quantification of cocaine was conducted using gas chromatography and mass spectrometry. The results of this study revealed a strain difference in total brain cocaine kinetics. Specifically, we observed that at 5 min onward, B6 mice cleared cocaine from the brain with a t1/2 estimated at 22.3 min, while distribution in D2 mice appeared to be incomplete until 15 min with a subsequent t1/2 estimated at 11.2 min. These results show that despite faster clearance by D2 mice, the prolonged time to distribution in this strain may help explain why D2 mice show initial greater locomotor activation by cocaine, compared to B6s.

Animals↗

PubMed1998

A practical in vitro sperm-egg binding assay that detects subfertile males.

A series of in vitro assays of sperm-egg binding were developed to identify potentially subfertile roosters. Initial assays used either segments of intact hen's egg perivitelline membrane (PVM) placed on a microscope slide or a heat-solubilized extract of PVM (HS-PVM) dried within a flat-bottomed microwell plate, with bound sperm detected with a DNA-specific stain and epifluorescence microscopy. An automated assay was developed using prestained sulfosuccinimidyl-7-amino-4-methylcoumarin-3-acetate-HS-PVM and enumeration of bound sperm with a fluorometric microwell plate reader. Four populations of chickens differing in fertility were evaluated with the following results: 1) the correlation across lines between in vitro sperm binding and fertility was 0.83 (N = 40; p < 0.0001); 2) correlations with other seminal parameters were low; and 3) the relationship between sperm binding and fertility was not linear, but a threshold plot allowed identification of males with low binding and low fertility. Motile sperm from roosters, turkeys, bulls, humans, mice, rams, and stallions bound in a dose responsive manner. Features of binding were revealed by both scanning and transmission electron microscopy. Use of this assay to cull males whose semen appears normal by traditional modes of analysis but differs in the obligatory trait of sperm-egg binding could be of value to avoid expensive progeny testing.

Animals↗

PubMed1995

Growth of broiler chickens in response to feed restriction regimens to reduce ascites.

A trial was conducted to investigate the impact of early feed restriction on ascites induced by cold temperatures and the subsequent effect on the whole body and breast muscle growth of broilers. Two feed restriction regimens were tested, consisting of limiting daily feed intake of the birds to 75% of the ME required for normal growth from either 4 to 11 d or from 7 to 14 d. At 21 d, half of the birds were moved to a cold house (17.8 C) to induce ascites. Five birds from each pen were killed for the breast muscle growth, Pectoralis major and Pectoralis minor, and heart and abdominal fat pad weights at 4, 7, 11, 14, 21, 35, and 49 d of the experiment. Birds in the cold house were heavier and had better feed conversion than birds in the control house at 49 d of age. This could be attributed to the high ambient temperatures (27 to 33 C) in the control house. The ad libitum birds had a significantly greater percentage of P. major than the feed-restricted birds. Exposure to cold temperatures caused significantly higher percentage of ascites from 21 to 49 d. Cold temperatures also increased the percentage of total heart and the right ventricle weight relative to total heart weight ratio at 35 and 49 d of age, suggesting that the surviving birds were more likely to develop ascites. Although catch-up growth was observed, the final body weight of feed-restricted birds was not the same as ad libitum birds. Early feed restriction reduced the incidence of ascites, but at the cost of breast muscle growth.

Age Factors↗

PubMed1995

Dietary cholesterol and fat saturation effects on plasma esterified and unesterified cholesterol in selected lines of Japanese quail females.

Three lines of Japanese quail females, randombred controls (CL), high response (HL), and low response (LL) lines, selected for plasma total cholesterol for 18 generations, were fed all-plant-source, nonatherogenic diets to which 0 or .5% cholesterol were added from 6 to 18 wk of age. In all three lines, plasma cholesterol increased when cholesterol was fed; however, responses were greater in the HL than in the LL line, with CL intermediate. In a second experiment, females of the three lines were fed, from 6 to 14 wk of age, four isocaloric, isonitrogenous plant-source diets to which were added: 1) 10% glucose monohydrate (cerelose); 2) 10% cerelose + .1% cholesterol; 3) 4% corn oil; or 4) 4% coconut oil. Baseline data obtained before feeding experimental diets indicated that the HL had significantly higher plasma total, esterified (EC) and unesterified (UEC) cholesterol than LL and that nonovulating females had higher concentrations of esterified cholesterol than ovulating females. Diets used did not affect cholesterol fractions in the ovulating females, although there were significant differences among lines. Dietary cholesterol significantly increased the ratio of EC to UEC. Sclerotic lesion scores were higher in the HL than the LL birds and in birds fed the coconut oil diet.

Analysis of Variance↗

PubMed1995

Comparative embryonic development in chickens with different patterns of postnatal growth.

We compared embryonic development of two lines of chickens that exhibit different patterns of postnatal growth. Classical staging techniques and morphological measurements of bone, cartilage, feather and intestines were used to test the hypothesis that differences in postnatal growth would be reflected in patterns of embryonic tissue partitioning. During the second quarter of incubation, the line with higher postnatal growth staged significantly earlier (i.e., was less developed overall) than the line with lower postnatal growth. Embryos from the line with higher postnatal growth exhibited less (i.e., allocated away from), bone growth (beak length, ossification of long bones), feather growth (number of feather papillae, length of primary), and eye development (number of lens sclera). There were no differences in gut development between the two lines. Our results show that different postnatal growth patterns are associated with changes in the pattern of embryonic reallocation between tissue types, even when gross morphological differences are not evident at hatching. We suggest that these differences in development represent periods when the embryo is allocating to hyperplastic growth of tissues such as muscle, as a means of increasing posthatching growth potential.

Animals↗

PubMed1994

Genetic control of food intake in chickens.

Genetic selection for body weight in broiler-type chickens has created a highly efficient omnivore capable of attaining a 2.0 kg body weight in 40-42 d of age with an overall feed conversion (feed consumed per unit of body weight) of less than two. The primary correlated response to the huge increases in the growth of chickens over the last 50 years has been increased feed intake. Although there is much independent data regarding the physiological systems controlling feed intake, there is a dearth of information regarding the inheritance of central and peripheral feed intake control mechanisms. Using four lines of chickens from a double selection experiment for exponential growth rate at different ages, we are investigating changes in both peripheral and central feed intake control mechanisms in response to selection. We have observed a genetic basis for neurotransmitter levels in the hatching chick, which seems to be related to selection for body weight. Diallel crossing experiments have demonstrated that catecholamine levels are inherited in a nonadditive manner, as is feed consumption immediately post-hatch, suggesting that sympathetic nervous activity (as defined by catecholamine and metabolite levels) may be involved in the inheritance of early feed intake in chickens. Further, the use of pharmacological substances (such as monosodium glutamate) known to alter food intake in mammals exhibit signs of genotype by treatment interactions for growth and hypothalamic neurotransmitter levels. These data suggest a research strategy to separate genetic changes in food intake from those related to responses in metabolism.

Animals↗

PubMed1994

A nonlinear dynamical (chaos) approach to the analysis of broiler growth.

Mathematical chaos has been observed in a number of biological areas, suggesting that order can be found in systems previously described as random. Nonlinear analyses were conducted to determine whether periodicity or chaos was evident in the growth responses of broiler chickens. Analyses of the absolute growth rate and growth rate acceleration were conducted for four lines of broilers selected at 14 or 42 d for high or low growth rates (Experiment 1) and for a commercial broiler strain (Experiment 2). Resulting Lyapunov exponents (LE) and correlation dimensions (CD) were statistically evaluated. Time series and return map graphics were analyzed. In both experiments, independence of day-to-day growth responses was indicated by low r2 values. In Experiment 1, there were significant differences between lines in growth rate (low, 9.1 +/- .3; high, 12.9 +/- .5 g/d) and the standard deviation of growth rate (low, 5.8 +/- .2; high 7.3 +/- .3 g/d). There were no significant differences for LE or CD values between lines or day of selection. In general, the positive LE, noninteger values of CD, and return map graphics in both experiments suggested the presence of chaotic dynamics. Evaluation of mathematical chaos in broiler growth may give insight into the dynamics and modeling of growth and diseases associated with growth.

Animals↗

PubMed1993

Effects of genotype and cryopreservation of avian semen on fertility and number of perivitelline spermatozoa.

1. The fertility of freshly diluted and cryopreserved samples of semen obtained from a population of chickens selected for duration of fertility of cryopreserved spermatozoa (FS line) and its unselected control (FC line) were compared over a range of spermatozoa concentrations (10, 40, 80, and 160 x 10(6) sperm/50 microliters insemination). 2. The spermatozoa of the FS line had greater fertility than spermatozoa of the FC line, whether freshly diluted or cryopreserved. Cryopreservation resulted in a reduction in fertility, regardless of line. There were no significant line by genotype interactions. 3. There were fewer spermatozoa from the FC line than the FS line found in the perivitelline membrane (perivitelline spermatozoa). The increase in number of perivitelline spermatozoa with increasing sperm concentration was greater in the FS than FC line. However, the slope of the increase in sperm number in the perivitelline membrane with increasing concentrations of cryopreserved spermatozoa was zero. 4. A minimum of 10(3) perivitelline spermatozoa must be found on day 2 post-insemination for duration of fertility to exceed three days. The ability to produce spermatozoa capable of reaching the forming perivitelline membrane appears to be a quantitative, rather than a qualitative, trait and may be subject to genetic manipulation.

Animals↗

PubMed1992

Heterosis for concentrations of dopamine, norepinephrine, their metabolites, and epinephrine in the chick hyperstriatum ventrale, hypothalamus, and optic tectum.

A complete diallel cross using both sexes was derived from four parental populations of chickens having divergent developmental rates. This paradigm was used to investigate the genetic architecture of the neurochemicals, norepinephrine (NE), epinephrine (EPI), 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine (DA), and 3-methoxy-4-hydroxyphenylglycol (MHPG). No sex differences were found for any genetic parameter investigated. Estimates of average line effects, maternal effects, and additive sex linkage were not significant. Highly significant heterosis, in the form of overdominance, was observed for catecholamine and metabolite concentrations. Hybrids exhibited significant line heterosis in the positive direction for NE, while heterosis for MHPG was observed in the negative direction for all crosses. Heterosis for EPI was both line and brain area specific with the hypothalamus showing greatest heterotic effects. DOPAC showed significant heterosis for all lines only in the optic tectum, and DA showed little heterosis specific to any line, cross, or brain area.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1992

Genetic architecture of carcass composition in chickens.

A cross-sectional diallel experiment was used to estimate the contribution of various types of genetic variation for the chemical components of the chicken carcass. Populations tested included a commercially developed sire line (CM), a fertility-selected broiler line (FS), and the pureline Jersey Giant (JG). Average line effects were significant for body weight and total carcass water, fat, and protein. Line effects were significant only for percentage fat and water. Maternal effects and additive sex linkage were not significant for any carcass component on an absolute or percentage basis. Significant average heterosis and sex by heterosis interactions were observed for abdominal fat pad weight and total carcass fat. Male hybrids exhibited a 29% decrease in abdominal fat pad size, but female hybrids exhibited a 7% increase. Significant heterosis was observed among females, but not males, for percentage carcass fat. Changes in carcass fat via hybridization produced the largest percentage change among males due to heterosis of the sex chromosomes. In the present experiment, negative heterosis for abdominal fat among male progeny accounted for approximately 65% of the overall reduction in fat content of the carcass.

Adipose Tissue↗

PubMed1992

Divergent selection for exponential growth rate at fourteen or forty-two days of age. 1. Early responses.

Athens-Canadian randombred chickens were divergently selected for exponential growth rate (EGR) to 14 or 42 days of age, resulting in four unique populations: 14L, 14H, 42L, and 42H. Exponential growth rate was calculated as: EGR = [ln b-ln a] + t; where a = hatching weight; b = weight at age of selection; and t = age of selection. In the S4 generation, 14H chicks had significantly greater EGR than 42H chicks at 14 but not 42 days. Chicks from the 42H line had significantly greater EGR than 14H chicks from 14 to 42 days. This meant that 14H chicks were significantly heavier than 42H chicks at 14 but not 42 days. Indeed, 14H chicks were consistently 5 to 10% heavier than the 42H chicks in each generation. Selection for EGR at 14 days was at least as effective in altering 42-day body weight as selection for growth rate at that age during the early generations of selection. Evidence of asymmetry existed for selection for EGR at 14 but not 42 days. Realized heritability of fast EGR14 was .29 +/- .08 (SE) whereas that of fast EGR42 was .15 +/- .09. Genetic correlation between fast EGR14 and fast EGR42 was 1.45, whereas the converse genetic correlation was .67. This would suggest that all the genes that influence 14-day growth influence 42-day growth, but not vice versa. Growth curve analysis supported the general hypothesis of growth, in that instantaneous growth rate was fastest in the 14H line, as was the decay of growth. Indeed, 14H birds were smaller at and beyond sexual maturity than 42H chickens.

Aging↗

PubMed1991

Genotype differences in catecholamine concentrations in hypothalamus, intramedial hyperstriatum ventrale, and optic tectum of newly hatched chicks.

This study was designed to compare catecholamine concentrations among three brain areas of four pureline populations of visually isolated chicks. The purelines used were a commercial male line, a fertility selected line, an unselected fertility control line, and unselected White Jersey Giants. In general, male chicks had significantly larger brain weights than females. Six catecholamine-related compounds (norepinephrine, epinephrine, L-DOPA, dopamine, DOPAC, and MHPG) were measured via HPLC-ECD. No significant differences in neurochemical concentration were observed for any line or brain area due to sex of the chick. The hypothalamus (HT) contained the greatest concentration of catecholamines in all lines, followed by the intramedial hyperstriatum ventrale (IMHV) and optic tectum (OT). The HT exhibited consistent lateralization in all lines with the right HT containing ca. 30% more catecholamines than the left HT. While no consistent lateralization was observed among the other brain areas, the IMHV exhibited significantly different degrees of lateralization among the populations. Neuronal activity, as measured by MHPG:NE and DOPAC:DA ratio varied by line within each brain area. There were line differences for MHPG:NE in the HT, IMHV, and OT, while line differences for DOPAC:DA were observed in the HT. Since differences among purelines have been demonstrated in this study, care must be given to precisely define the genotype of chicks used in behavioral and neurochemical research.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1991

Effects of monosodium glutamate on lines of chickens having different juvenile exponential growth rates.

MSG (4 mg/g BW) or the equivalent molar ratio of NaCl were injected subcutaneously into chicks from four populations of chickens derived from a double selection experiment [(1) low exponential growth rate (EGR) to 14 days of age (14L), (2) high EGR to 14 days of age (14H), (3) low EGR to 42 days of age (42L) and high EGR to 42 days of age (42H)]. MSG significantly influenced growth in chickens, but the absolute effect was genotype and sex dependent. Weights of abdominal fat pads were ranked among lines according to the sequence 42H, 14H, 42L and 14L. MSG significantly increased fat pad size by 51%, independent of genotype or sex. MSG significantly decreased breast weight in females and males by 7%. The higher percent fat pads and lower breast weights associated with MSG are indicative of growth due to fat accretion rather than protein deposition.

Adipose Tissue↗