The objective of this study was to assess the effectiveness of a Nycodenz gradient enrichment method to enrich a dissociated single cell suspension of porcine testicular cells for spermatogonia, and to observe the separated fractions from the gradient over a 14-day culture period for cell viability and number of spermatogonia in culture. Two germ cell specific genes, VASA and DAZL, were utilized for detection of spermatogonia using immunohistochemistry. The control group included cultures generated from the enzymatic digestion of porcine testes prior to the enrichment protocol for each replicate. The NycoDenz gradient consistently separated the isolated cell suspension into three distinct layers and a pellet, all of which were assessed for spermatogonial enrichment. Testis cells were isolated and seeded in culture on day 0. Cell viability and percent of spermatogonia was assessed on day 0, 7, and 14 of culture. Viability was determined using trypan blue exclusion assay and quantified using a hemocytometer. Spermatogonia were morphologically identified as round, plump cells with a large amount of cytoplasm. Visualization of spermatogonia was facilitated by immunostaining with DAZL and VASA polyclonal antibodies and cells exhibiting morphological characteristics in addition to bright, concentrated fluorescence were counted as spermatogonia.

A major factor in maximizing microbial protein synthesis is the availability of energy and protein in the diet. Our objective was to determine the effect of fermentable carbohydrate and protein on microbial fermentation. Diets were formulated using three ingredients, soybean meal (SBM), ground corn (GC) and soybean hulls (SBH). Corn and SBH were used in ratios of 60:20, 40:40 or 20:60, respectively to prepare high, medium or low non-fibrous carbohydrate (NFC) diets. Soybean meal was included either unextruded (control) or extruded at low, medium or high temperature. Degradability of the N fractions in the control, low, medium and high soybean meal were 97, 80, 80 and 60%, respectively. Diets were arranged as a 3 x 4 factorial (3 levels of corn/soybean hulls and 4 levels of protein) and analyzed as a completely randomized block design. There were no statistically significant interactions seen between NFC and protein sources. Total volatile fatty acids were affected (P<0.01) by the NFC with 78.5, 63.2 and 71.5 mM with increasing NFC levels. The NFC level affected the acetate and butyrate whereas the protein source had an effect on the propionate. Molar ratios of acetate, propionate and butyrate averaged 60.1, 31.0 and 6.79, respectively. Varying the level of fermentable carbohydrate had a negative linear affect on ruminal pH (P<0.01). Extrusion did not alter pH greatly P>0.67). Higher extrusion temperatures altered ammonia concentrations when compared to control or low extrusion. In the low NFC diets, the medium and high extrusion increased (P<0.10) ammonia concentration (29.8 and 32.6 mg/dl, respectively) when compared with control and the low (18.9 and 23.4 mg/dl, respectively). Methane concentration averaged 308 nmoles/ml and was affected by both the NFC treatment and protein source. The high and medium NFC diets increased (P<0.01) bacterial nitrogen percentage (9.0 and 9.5%, respectively) compared to the low NFC diet (8.7%). Data suggest that the fermentability of the structural carbohydrates in SBH was similar to the high starch corn diets. Furthermore, large differences in protein degradability did not seem to have a major impact on microbial fermentation.

<p>Today, dairy farmers in the U.S. are faced with the challenge of reducing the cost of producing milk. Milk prices have risen very little in the past decade, while the cost of producing milk has risen steadily. In North Carolina alone, dairy farm numbers have dropped more than 30% in the last ten years, and the trend is expected to continue. Dairy farmers have been forced to increase their profitability to stay in business. In addition, farmers have been forced to comply with stricter environmental regulations. Over the past few years, interest has been shown in intensive management rotational grazing systems. This four-year comparison trial was designed to compare the milk production, herd health, reproductive performance, and environmental impacts of pasture-based and confinement feeding systems using Holstein and Jersey cattle for the Mid-Atlantic region. The project had both Spring and Fall calving herds with breeding via artificial insemination in 75-day periods. Each seasonal herd replicate had 36 cows on pasture and 36 cows in the confinement group. Similar numbers of Holsteins and Jerseys were included in each year. Paddocks grazed comprised 29 ha of cool and warm season pasture species in 37 paddocks for year-round grazing. Pasture-fed cows received variable amounts of grain and baled silage as needed depending upon pasture availability. Confinement cows were housed in a covered freestall barn with access to an exercise lot and received a total mixed ration with corn silage as the primary forage. Confinement cows produced significantly more milk than pasture-fed cows, both for total lactation and average daily production. Reproductive performance of the two treatments did not differ with an overall 75-day pregnancy rate of 68%. Jerseys in both systems did have higher percentages of cows inseminated (96.5%), conception rate (59.6%), and 75-day pregnancy rate (78%) compared to Holsteins (86%, 49%, 57.9% respectively). The percentage of cows infected with at least one case of clinical mastitis was higher in the confinement herd than the pasture-fed herd (43% vs. 24%) with Holsteins higher than Jerseys (41% vs. 26%). Interactions of breed and feeding system and average somatic cell count scores were not significantly different. Pasture-fed cows had lower average body condition scores than confinement cows, ranging from 0.2 to 0.6 points lower on a 5-point scale.In a short-term trial, intake measurements were taken from pasture-fed Holsteins and Jerseys consuming a grain supplement. This supplement was similar to those that were fed to the pasture-fed cows during the four-year trial. It was determined that Jerseys could consume as much as Holsteins at three different feeding levels (6.8, 4.5, and 2.3 kg/cow per feeding). This experiment showed that in certain time frames, Jersey cattle can consume equal amounts of supplements compared to Holsteins. Therefore in mixed groups Jerseys can consume relatively more supplemental energy relative to body size and milk production compared the Holsteins. In another short-term trial using cows from a spring season replicate, milk samples were obtained from pasture-fed and confinement-fed cattle and analyzed for fatty acid composition. The pasture grazed was a warm-season pasture, while the confinement-fed cattle consumed a corn-silage based TMR. The major fatty acid of interest was conjugated linoleic acid (CLA), which has been shown to be a potent anticarcinogen. Concentrations of CLA were 80% higher in pasture-fed cattle compared to the confinement-fed cattle. In addition concentrations of CLA were higher in Holsteins compared to Jerseys. To study the distribution of manure in a pasture-based system, pastured cows were observed for several 24-h periods. Data included: (1) times and location of all feces and urine events from eight cows, observed while in the pasture, feed area, milking parlor or in transit; and (2) all urine and feces events on pasture for all 36 cows each grazing period. The locations of urine and feces events were surveyed, mapped and analyzed. Percentages of the manure events in each area were highly correlated with time spent in each area (r= .99). Feces and urine (estimated at .12 m2 and .36 m2, respectively) from six observational periods covered 10% of the total paddock. Within 30 m2 of the portable waterer and gate, concentrations of feces and urine from the warm season observations were significantly greater than concentrations during the cool season observations. Manure on pasture was relatively evenly distributed over multiple grazing periods with the exception of the area around the water tank during summer grazings. These experiments showed that when compared to confinement-fed cattle, pasture-fed cattle produced less milk, produced more conjugated linoleic acid, had less mastitis and had lower body condition scores, while reproductive performance did not differ between the two groups. Jerseys had less mastitis, produced less conjugated linoleic acid, and performed better reproductively when compared to Holstein cattle. In addition, pasture-fed Jersey cattle can consume as much supplemental grain in certain time frames as pasture-fed Holstein cattle. Manure distribution on a pasture-based system is highly correlated with time spent in an area and is fairly evenly distributed over the paddock area over multiple grazing periods except for the area around the water tank during heat stress temperatures.<P>

<p>A series of experiments was conducted to examine the absorption and post-absorptive metabolism of zinc (Zn) from inorganic and organic sources. Results of an in vivo experiment, using Holstein bull calves as models, suggested that, when Zn was supplemented at 20 mg Zn/kg DM for 98 d, Zn source had minimal impact on plasma or tissue Zn concentrations. However, when Zn was supplemented at 500 mg Zn/kg DM for 12 d, plasma and tissue Zn concentrations were greater in bulls that received Zn proteinate (ZnProt) than in those that received ZnSO and Ca only, uptake and transport of Zn from inorganic and organic Zn sources were similar. However, when added at high concentration in the presence of dietary antagonists, Zn uptake from organic sources appeared to be greater than from inorganic sources. Further research is certainly warranted to more clearly define differences in Zn absorption that may exist between inorganic and organic Zn sources at different dietary levels.<P>

<p>HASTY, JENNIFER. EFFECTS OF VITAMIN E SUPPLEMENTATION ON PORK QUALITY CHARACTERISTICS OF HAMPSHIRE CROSSES AND BERKSHIRE CROSSES. (Under the direction of Eric van Heugten). An experiment was conducted to investigate whether pork quality characteristics could be improved by feeding supra-nutritional levels of vitamin E (as a-tocopheryl acetate) to Berkshire x PIC and Hampshire x PIC finishing pigs. Diets contained 0, 75, 150, 300 or 600 mg a-tocopheryl acetate/kg and were fed ad libitum for six weeks. Pigs were biopsied on 0, 21 and 42 d to evaluate potential pork quality. After the six-week feeding period, pigs were humanely slaughtered at a commercial facility and the right loin was taken from previously biopsied pigs for pork quality measurements. Chops were packaged and placed in refrigerated illuminated conditions and displayed for 0, 2, 4, 6 and 8 d. Loin sections were vacuum packaged, refrigerated and stored for 25, 35, 45 and 55 d. Supplemental vitamin E had no effect on improving average daily gain and tended to increase average daily feed intake. Average daily gain and gain:feed were greater for the Hampshire crosses and average daily feed intake was greater for the Berkshire crosses over the six-week feeding period. Supplemental vitamin E had no effect on carcass characteristics but there were differences between the two genotypes with Berkshire crosses having greater back fat and a lower percent yield, loin eye area, and lean percent. Supplemental vitamin E had no effect on biopsy fluid loss or pH. Hampshire crosses had greater fluid loss measured on day 42 than Berkshire crosses. There was no effect of supplemental vitamin E on initial (taken 45 min after slaughter) or ultimate (taken 24 hrs after slaughter) pH or temperature of the carcasses. There were no differences between genotype for initial pH and initial or ultimate temperature; however, ultimate pH was greater for Berkshire crosses. Serum and tissue vitamin E levels both increased with increasing levels of vitamin E in the diet and tissue vitamin E levels were greater for Hampshire crosses. Drip loss taken 24 hrs after slaughter was not affected by supplemental vitamin E and was lower in Berkshire crosses. However, there was a tendency for increasing level of vitamin E to decrease drip loss for the display chops of Hampshire crosses. Drip loss for the vacuum packaged loin sections was not affected by supplemental vitamin E and was lower in Berkshire crosses. Minolta L* values, taken 24 hours after slaughter, were not influenced by vitamin E. There was a trend for increasing levels of vitamin E to linearly increase a* and b* values. Hampshire crosses had greater a* values than Berkshire crosses, indicating redder meat. Supplemental vitamin E had no effect on any of the Minolta color values for the display chops or chops from the vacuum packaged loin sections. Berkshire crosses had lower L* and b* values and Hampshire crosses had greater a* values for both the display chops and chops from the vacuum packaged loin sections. TBARS values measured for samples collected 24 hrs after slaughter were not affected by supplementation of vitamin E but were greater for Hampshire crosses. TBARS values for Hampshire crosses were consistently greater over the display period. For day 4, 6, and 8, TBARS values decreased with increasing levels of vitamin E in the diet. No differences were seen in 0 or 2 d samples. TBARS values for Hampshire crosses decreased linearly with increasing levels of vitamin E in the diet but no effects were seen for Berkshire crosses. TBARS for chops from vacuum packaged loin sections were not affected by supplemental vitamin E and did not differ between genotype.<P>

<p>Feed mills demand routine techniques to analyze digestible amino acids in highly variable animal meals. As routine tools, infrared spectroscopic predictions of digestible amino acids require reference samples assayed in vivo. Lack of reference samples resulting from costly and time-consuming in vivo assays has limited infrared spectroscopic applications. To remove this limitation, an in vitro assay mimicking in vivo digestion in swine was sought as a replacement to build the reference database.<p>Pepsin and pancreatic proteases used in the in vitro assays produce autolysates that are assayed as digestible amino acids. To correct this contamination and define incubation time for efficient use of the proteases, the autolysis of these proteases was studied. Correction of enzyme contamination with enzyme blank incubations and incubation time of 24 hours for pepsin and 96 hours for pancreatic proteases were proposed (Chapter III and IV).<p>In vitro digestion focused on maximal hydrolysis of peptide bonds with minimal enzyme usages for restriction of enzyme contamination. The minimal enzyme usage was determined to be 6.5% (enzyme to substrate ratio) (Chapter V).<p>Study on absorption of peptides in swine revealed that all soluble in vitro peptides could be estimated as digestible in vivo. Average in vitro digestibility coefficients were comparable to in vivo for a number of amino acids but mismatch occurred for individual samples. In vivo digestible amino acids, though, could be predicted with in vitro digestible amino acids. For example, lysine was predicted with an error of 0.27% (Chapter VI).<p>Total and digestible amino acids were predicted with near infrared reflectance spectroscopy (NIRS) and mid infrared Fourier transform infrared spectroscopy (FTIR) but not with Raman spectroscopy. Infrared spectroscopic prediction errors for digestible lysine were 0.27% for near infrared spectroscopy and 0.26% for mid infrared spectroscopy. Total amino acids seemed better predicted than digestible amino acids by infrared spectroscopy (Chapter VII). <p>The study showed that as routine techniques, infrared spectroscopy could potentially replace both in vivo and wet chemical analyses of amino acids.<P>

<p>PALA, AKIN. Effects of Three Twice-a-Year Breeding Schedules in Four Breeds of Sheep. (Under the direction of ODIS WAYNE ROBISON and ROGER LEE McCRAW).Straightbred populations of Dorset, Finnsheep, Composite I (50% Finnsheep, 25% Dorset, and 25% Rambouillet), and Composite II (50% Finnsheep, 25% Suffolk, and 25% Targhee) sheep were evaluated under three different twice-a-year breeding schedules. Ewes were exposed for 32 d starting on August 13 and February 5 for schedule I, on September 15 and March 10 for schedule II, and on October 22 and April 11 for schedule III. Approximately 100 ewes of each breed were exposed to rams during each breeding season. The experiment was conducted for five complete cycles starting with matings in the fall of 1984 and ending with matings in the spring of 1989. Data were obtained on 9419 lambs produced from 2334 ewes and 257 rams. Traits of primary interest were conception rate, litter size at birth, weaning weight, weaning weight adjusted for conception rate, litter weaning weight and litter weaning weight per ewe exposed. Lactation status had a significant effect on conception rate and litter size while number of lambs suckling did not have a significant effect on conception rate. Composite I ewes had the highest conception rates and litter size (P 0.10), both had larger litters (P < 0.01) than the other two breeds. Ewes giving birth in spring had the highest conception rate and heaviest lambs (P < 0.01). Animals bred in schedule I had the heaviest and largest litters, highest conception rate, heaviest lambs and highest litter weaning weight per ewe exposed (P < 0.01). Efficiency of twice-a-year lambing systems is greatly affected by breeds, breeding schedules and seasons. Twice-a-year lambing programs must use the correct breeding schedule. Further, using composite breeds can be of great benefit.Genetic parameters for conception rate, litter size at birth, weaning weight, weaning weight adjusted for conception rate, litter weaning weight and litter weaning weight per ewe exposed were estimated using REML with animal models. Heritability estimates for conception rate were adjusted to a normal scale. Standard errors of heritabilities for conception rate were calculated using three methods, including bootstrapping. Heritabilities were estimated overall and within breed. Estimates of heritability for conception rate ranged from 0.17 &#177 0.01 (Dorset) to 0.27 &#177 0.01 (Composite I). Heritability estimates for litter size were 0.08 &#177 0.01, 0.19 &#177 0.01, 0.14 &#177 0.01 and 0.13 &#177 0.01 for Dorset, Finnsheep, Composite I and Composite II, respectively. Heritabilities for litter weaning weight and litter weaning weight per ewe exposed were similar across breeds and ranged from 0.31 &#177 0.01 to 0.36 &#177 0.01. Heritability for weaning weight was higher for Dorset (0.65 &#177 0.01) than for Composite I (0.57 &#177 0.01). Finnsheep and Composite II had similar heritabilities (0.41 &#177 0.01). Overall heritabilities for litter weaning weight, litter weaning weight per ewe exposed, weaning weight, weaning weight adjusted for conception rate, conception rate and litter size were 0.33 &#177 0.02, 0.35 &#177 0.01, 0.64 &#177 0.01, 0.64 &#177 0.01, 0.24 &#177 0.01 and 0.16 &#177 0.01, respectively. Overall Spearman rank-order correlations of litter weight traits with conception rate or litter size ranged from 0.81 to 0.88. Correlations within breed were generally high and positive. Genetic correlations between dry and lactating ewes for conception rate and litter size were small (0.009 and 0.108, respectively), indicating that rank of sires was inconsistent under different environments (lactation status). Selection should be practiced among lactating animals for conception rate and litter size in twice-a-year lambing systems.Heritability estimates were moderate to high for weight traits and low to moderate for reproduction traits, indicating that selection in twice-a-year lambing programs is feasible. There was no substantial evidence that heritabilities and rank correlations were different among the four breeds. Litter weaning weight may be increased along with conception rate and litter size in a selection program based on twice-a-year lambing. Small genetic correlation between dry and lactating ewes indicated that grouping sires according to the lactation status of the ewes is necessary in a selection program.<P>

No description available.

Studies on cytoskeletal proteins and protein phosphorylation

Purification and characterization of leukotriene