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The present study aimed to use an in vitro follicle culture (IVFC) biotechnique as a tool to evaluate the influence of whole flaxseed as a feed supplementation in the diet on the in vitro development of caprine early antral follicles (EAFs) and further embryo production. In total, 18 adult goats were homogeneously allocated into two diet groups: Control and Flaxseed. EAFs from both experimental groups (300-400 µm) were isolated and cultured in vitro for 18 days. After IVFC, recovered cumulus-oocyte complexes were submitted to in vitro maturation, and subsequently to IVF and in vitro embryo culture. The endpoints evaluated were follicular growth and morphology, oocyte recovery rate and diameter, sperm penetration, pronuclei formation, embryo development, and estradiol production. The addition of the whole flaxseed in the diet did not affect (P > 0.05) follicular growth and diameter. A higher (P < 0.05) percentage of oocytes ≥ 110 µm was recovered from the flaxseed treatment. However, the sperm penetration rate was higher (P < 0.05) in the control treatment when compared with the flaxseed treatment, but no differences were found regarding the rate of fertilization nor cleaved embryos. In conclusion, dietary flaxseed increased the recovery rate of fully grown oocytes, but it did negatively affect the sperm penetration rate, even though there was no further effect on the cleavage rate.

Sows from three university research facilities ( n = 245) were stratified by parity and initial body weight (BW), and within outcome groups, randomly assigned to fortified corn- and soybean meal-based control or organic trace mineral-supplemented, gestation (3,339 kcal/kg ME; 0.62% standradized ileal digestible [SID] lysine), and lactation (3,374 kcal/kg ME; 0.97% SID lysine) diets. Control gestation and lactation diets were supplemented with inorganic trace minerals (120 ppm Zn from ZnO, 30 ppm Cu from CuSO 4 , and 50 ppm Mn from MnSO 4 ), and the experimental diets contained the same total level of minerals but complexed organic trace minerals replaced 50% of the inorganic trace minerals. Sows were fed to condition during gestation and on an ad libitum basis during lactation. Sow BW (breeding, d 110 of gestation, 48 h post-farrowing, and weaning) and feed consumed were recorded. During gestation, control sows tended to gain less weight (60.4 vs. 64.6 kg, P = 0.06) and consumed less feed (263.5 vs. 264.8 kg, P = 0.05), and had poorer Gain:Feed (G:F) (0.27 vs. 0.29, P = 0.04) than sows fed the organic trace minerals. Sow average daily feed intake (ADFI) during lactation was similar ( P = 0.28) between groups (4.93 vs. 4.74 kg for control and treated sows, respectively). Number of pigs born alive (11.4 vs. 10.9, P = 0.24) and weaned (10.2 vs. 9.8, P = 0.18), and pig pre-weaning average daily gain (ADG) (0.27 vs. 0.27 kg/d, P = 0.77) and mortality (13.1 vs. 12.9%, P = 0.92) were similar for control and treated sows, respectively. Results of the current study demonstrate that sows fed diets supplemented with organic trace minerals displayed similar reproductive performance, but improved weight gain and G:F during gestation compared with sows fed inorganic trace minerals., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Exposure to contaminants in the field is a reality for deployed canines. To date, there is no data evaluating the benefits of training for handlers associated with canine decontamination efforts. The objective of our work was to investigate the impact of handler training on the reduction of oil-based contaminants in working canines. Canine teams ( n = 10) were randomly assigned to either TRAINED or UNTRAINED groups. Each team (handler and dog) in the TRAINED group received 30-minutes of interactive training using an illustrated guide on proper utilization of equipment provided. Teams in the UNTRAINED group received the same equipment and illustrated guide but no interactive training. Decontamination efforts were measured using an oil-based pseudo-contaminant (GloGerm®, Moab, UT) topically applied to four anatomical locations: cranial neck, between the shoulder blades, left medial hindlimb and left hind paw with pre- and post-washing images collected from a fixed distance of 20 inches. Visual assessment of contaminant reduction was scored as follows: 0 = <24% contaminant reduction; 1 = 25-50% contaminant reduction; 2 = 51-75% contaminant reduction; and 3 = >76% contaminant reduction. No score discrepancies >1 were reported between reviewers. Trained handlers were more effective at contamination reduction (P = .0093) as compared to their untrained counterparts. These results indicate that handlers, when properly trained, can achieve reduction of oil-based contaminants with a disposable decontamination kit and a garden hose.

Aim: The present study evaluates the effect of different concentrations of antioxidants (catalase - CAT and alpha lipoic acid - ALA) on the follicular activation and morphology, DNA damage, ROS production, and mitochondrial activity in vitrified sheep ovarian tissue., Methods: This experiment was divided into two steps. First, ovarian fragments were distributed into the following treatments: fresh tissue or control (CTR), incubation (INC), vitrification without antioxidant (VWA), with CAT (10, 20, or 40 IU mL -1 ) or ALA (25, 50, or 100 μM mL -1 ). After vitrification/warming, the fragments were additionally incubated for 24 hours and evaluated for morphology and follicular activation, as well as reactive oxygen species (ROS) levels in the culture medium. For the second step, other ovarian fragments were submitted to CTR, VWA, CAT40, and ALA100. After vitrification/warming, the fragments were incubated for 24 hours and evaluated by cell density of ovarian stroma, DNA damage, and mitochondrial and intracellular ROS levels., Results: The percentage of morphologically normal follicles in vitrified ovarian tissue in the presence of ALA in all concentrations did not differ (p > 0.05) from fresh tissue or CTRs. The percentage of activated follicles was higher in ALA100 μM mL -1 than those observed for the treatments INC, CAT (40 IU mL -1 ), or ALA (25 or 50 μM mL -1 ). The use of CAT affected (p < 0.05) the density of stromal cells (40 IU mL -1 ), ROS levels (10 and 20 IU mL -1 ), as well as DNA damage revealed by ©H2AX (40 IU mL -1 )., Conclusions: Although 100 μM/mL of ALA did not alter intracellular ROS, this concentration reduced the levels of ROS in the culture medium, preserved both the follicular morphology, as well as the mitochondrial activity, promoted follicle activation, and protected the follicles from DNA damage.

The aims of this study were to evaluate (1) the survivability of white-tailed deer ovarian tissue after cryopreservation by slow-freezing (SF) and vitrification (VIT) techniques and in vitro culture (IVC) for up to 7 days, and (2) the effects of cryopreservation techniques on protein expression of proliferative and apoptotic markers of ovarian tissue pre- and post-in vitro culture. Ovaries (n = 14) of seven white-tailed deer fawns (<1.5 years old) were used. Ovarian cortexes were cut into fragments (2 × 2 × 0.5 mm) and split into nine treatment groups: (1) fresh noncultured control, (2) fresh-IVC 1 day, (3) fresh-IVC 7 days, (4) SF noncultured, (5) SF-IVC 1 day, (6) SF-IVC 7 days, (7) VIT noncultured, (8) VIT-IVC 1 day, and (9) VIT-IVC 7 days. Preantral follicle morphology, class distribution, and density; stromal cell density; EGFR, Ki-67, Bax, and Bcl-2 protein expression; and DNA fragmentation were assessed. Results showed that: (i) white-tailed deer fresh ovarian tissue can be cultured for up to 7 days, preserving the tissue integrity and 50% of morphologically normal preantral follicles; (ii) cryopreservation of white-tailed deer ovarian tissue by either slow-freezing or vitrification does not disrupt markers of proliferation and apoptosis after thawing; (iii) ovarian fragments cryopreserved by the vitrification method had greater follicle viability during in vitro culture than the slow-freezing method; and (iv) fragments cryopreserved by slow-freezing suffered apoptosis earlier than those preserved by vitrification. The findings herein reported advance knowledge towards development of adequate cryopreservation protocols for long-term banking programs for Cervidae species., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The effects of epidermal growth factor (EGF) concentrations (0, 10, 50, and 100ng/ml) on in vitro culture (IVC) of equine preantral follicles were evaluated using histology, estradiol and reactive oxygen species (ROS) production and metabolomics. After IVC, the percentage of normal follicles was lower (P<0.05) for all treatments when compared to non-cultured control. EGF 50ng/ml treatment had more (P<0.05) normal follicles at Day 7 of culture when compared with EGF 0 and 100ng/ml. EGF 50ng/ml had more (P<0.05) developing follicles than the 0ng/ml and 10ng/ml EGF treatments. Follicular and oocyte diameters were greater (P<0.05) with EGF 50ng/ml than the other cultured treatments, but similar (P>0.05) to the non-cultured control. From Day 1 to Day 7 estradiol production increased (P<0.05) in all EGF treatments. EGF 50ng/ml was the only treatment that maintained ROS production through IVC. Metabolomics profiles of the spent media indicated that eleven ions from variable influence in the projection (VIP) scores were higher represented in the EGF 50ng/ml treatment. In conclusion, EGF 50ng/ml treatment maintained follicle survival and ROS production, and promoted activation of cultured equine preantral follicles enclosed in ovarian tissue., (Copyright © 2017. Published by Elsevier Ltd.)

The vitrification of preantral follicles followed by in vitro growth (IVG) could be valuable to produce fertilizable oocytes. However, the meiotic resumption rates of oocytes cultured from vitrified secondary follicles (SF) have been reported as suboptimal. This study aimed to verify two base media (alpha modification of minimum essential medium, α-MEM, and tissue culture medium 199, TCM199) on vitrified SF regarding different requirements during IVG. Sheep ovarian fragments were divided in six groups: (1) Fresh groups (Control α-MEM and TCM199): SF without vitrification; (2) Follicle-Vitrified (Follicle-Vit α-MEM and TCM199): SF vitrified after isolation; and (3) Tissue-Vitrified (Tissue-Vit α-MEM and TCM199): SF vitrified enclosed in ovarian fragments and, subsequently, isolated. The isolated SF were submitted to IVG for 18 days. Thereafter, the recovered cumulus-oocyte complexes (COCs) underwent in vitro maturation (IVM) and evaluation of chromatin configuration. Follicular granulosa cells were analyzed for their gene expression of Bax, Bcl2, and Connexins (CX) 37 and 43. COCs from in vivo antral follicles were used as in vivo control. Data were analyzed by analysis of variance, Tukey, and chi-square tests. Differences were considered significant if p-value is <0.05. Follicle-Vit groups had higher (p < 0.05) percentage of antrum formation compared with Tissue-Vit groups. Vitrification did not affect (p > 0.05) oocyte diameter postmaturation. Oocytes from Follicle-Vit in α-MEM reached metaphase II stage after IVM. Gene expression for CX37, CX43, and Bax was lower in Tissue-Vit groups. For Bcl2, the gene expression was the opposite. In conclusion, during IVG for 18 days, maximal oocyte meiotic resumption was not negatively impacted by vitrification and was greatest for isolated SF using α-MEM as a medium.

The knowledge about ovarian reserve is essential to determine the reproductive potential and to improve the methods of fertility control for overpopulated species, such as white-tailed deer (Odocoileus virginianus). The goal of this study was to evaluate the effect of age on the female reproductive tract of white-tailed deer, focusing on ovarian features. Genital tracts from 8 prepubertal and 10 pubertal females were used to characterize the preantral follicle population and density, morphology, distribution of follicular classes; stromal cell density; and apoptosis in the ovary. In addition, uterus and ovary weights and dimensions were recorded; and the number and the size of antral follicles and corpus luteum in the ovary were quantified. Overall, fawns had a greater (P < 0.05) preantral follicle population, percentage of normal follicles, and preantral follicle density than does. The mean stromal cell density in ovaries of fawns and does differed among animals but not between age groups. The apoptotic signaling did not differ (P > 0.05) between the ovaries of fawns and does. However, apoptotic ovarian cells negatively (P < 0.001) affected the preantral follicle morphology and density, and conversely, a positive correlation was observed with stromal cell density. As expected, the uteri and ovaries were larger (P < 0.002) and heavier (P < 0.001) in does than in fawns. In conclusion, this study has shown, for the first time, the preantral follicle population and distribution of classes, rate of morphologically normal follicles, and density of preantral follicles and stromal cells in white- tailed deer. Therefore, the findings herein described lead to a better understanding of the white-tailed deer ovarian biology, facilitating the development of new methods of fertility control.

Colour Doppler ultrasonography was used to compare the ability of preovulatory follicle (POF) blood flow and its dimensions to predict the size, blood flow and progesterone production capability of the subsequent corpus luteum (CL). Cows (n=30) were submitted to a synchronisation protocol. Follicles ≥7mm were measured and follicular wall blood flow evaluated every 12h for approximately 3.5 days until ovulation. After ovulation, cows were scanned daily for 8 days and similar parameters were evaluated for the CL. Blood samples were collected and plasma progesterone concentrations quantified. All parameters were positively correlated. Correlation values ranged from 0.26 to 0.74 on data normalised to ovulation and from 0.31 to 0.74 on data normalised to maximum values. Correlations between calculated ratios of both POF and CL in data normalised to ovulation and to maximum values ranged from moderate (0.57) to strong (0.87). Significant (P<0.0001) linear regression analyses were seen in all comparisons. In conclusion, higher correlations were observed between the dimensions of POF and/or CL and blood flow of both structures, as well as POF and/or CL blood flow with plasma progesterone concentrations of the resultant CL. These findings indicate that follicle vascularity coordinates CL blood flow and progesterone production in synchronised beef cows.

The aim of the present study was to evaluate the effect of growth hormone (GH) and vascular endothelial growth factor (VEGF) added alone, sequentially or in combination, in the presence of insulin at physiological concentration (10 ng/mL) on the IVC of two different follicular categories: preantral (experiment 1; Exp.1) and early antral (experiment 2; Exp.2). Isolated follicles were individually cultured for 24 (Exp.1) and 18 days (Exp.2) in the following treatments: αMEM + (Control), or Control medium supplemented with 50 ng/mL GH (GH), 100 ng/mL VEGF (VEGF), the combination of both (GH + VEGF), GH during the first 12 days and VEGF from Day 12 until the end of the culture (GH/VEGF) and vice versa (VEGF/GH). At the end of the culture, cumulus-oocyte complexes from in vitro-grown follicles were recovered and subjected to IVM. The following end points were evaluated: Follicle morphology, growth rates and antrum formation, production of estradiol, progesterone and testosterone, oocyte viability and meiotic stage, as well as relative expression of LHR, Amh, HAS2, PTGS2, CYP17, CYP19A1, and 3βHSD. A considerable amount of viable fully grown oocytes were recovered after the IVC of early antral follicles in all treatments. Nevertheless, the GH treatment presented the highest percentage of fully grown oocytes (60%), mean oocyte diameter (117.74 ± 2.61 μm), and meiotic resumption (50%). Furthermore, GH treatment produced higher (P < 0.05) rates of metaphase II oocytes than all the other treatments, and similar LHR, Amh, and PTGS2 transcript levels to in vivo. Contrary to early antral follicles, preantral follicles were not affected by medium supplementation. In conclusion, the addition of GH to a culture medium containing physiological concentrations of insulin improves oocyte growth and maturation after the IVC of goat early antral follicles., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The deleterious effect of heat stress (HS) on competence of oocytes from antral follicles is well recognized, but there is a lack of data regarding its impact on the viability and growth of preantral follicles. In this study, we used in vitro preantral follicle cultures to investigate the effects of HS on the following parameters: survival and development of primordial follicles after in vitro culture of ovarian fragments (experiment I); growth and antrum formation of isolated advanced secondary follicles (experiment II); and maturation rates after in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) from antral follicles (>2-6 mm) grown in vivo (experiment III). Furthermore, the following end points were evaluated in all experiments: follicle/oocyte survival, reactive oxygen species (ROS), estradiol (E2) and progesterone (P4) production, as well as mRNA expression for select genes related to stress (HSP70) and apoptosis (MCL1 and BAX). In all experiments, HS consisted of exposing the structures (ovarian fragments, isolated preantral follicles and COCs) to 41 °C for 12 hours and then to 38.5 °C until the end of the culture (7 days for experiments I and II and 24 hours for experiment III). The temperature for the control group was held at 38.5 °C for the entire culture period. Heat stress increased (P < 0.05) the percentage of developing follicles (intermediate, primary, and secondary follicles) at 12 hours and increased levels of ROS at all evaluated time points (12, 24 hours, and D7), when compared to the control (experiment I). Heat stress did not affect (P > 0.05) any identified end points when preantral follicles were cultured in their isolated form (experiment II). However, in experiment III, HS decreased (P < 0.05) both the rates of metaphase II after 24 hours and E2 production at 12 hours of IVM. Moreover, HS increased (P < 0.0001) levels of P4 after IVM and ROS production at every evaluated time point, compared with the control (12 and 24 hours). In conclusion, HS caused: (1) early activation of primordial follicles; (2) an increase in ROS production by early preantral follicles enclosed in ovarian tissue and by COCs; (3) a short-term reduction of E2 production by COCs; and (4) an increase in P4 secretion from COCs. However, HS did not affect in vitro culture of advanced isolated secondary follicles. Experimental evidence indicates that preantral follicles are less sensitive to HS than COC., (Copyright © 2016 Elsevier Inc. All rights reserved.)

This study investigated the effect of adding different concentrations of bovine recombinant follicle-stimulating hormone on the IVC of equine preantral follicles enclosed in ovarian tissue fragments. Randomized ovarian fragments were fixed immediately (fresh noncultured control) or cultured for 1 or 7 days in α-MEM(+) supplemented with 0, 10, 50, and 100 ng/mL FSH and subsequently analyzed by classical histology. Culture media collected on Day 1 or Day 7 and were analyzed for steroids (estradiol and progesterone) and reactive oxygen species (ROS). After Day 1 and Day 7 of culture, 50-ng/mL FSH treatment had a greater (P < 0.05) percentage of morphologically normal follicles when compared to the other groups, except the 10-ng/mL FSH treatment at Day 1 of culture. The percentage of developing follicles (transition, primary, and secondary), and follicular and oocyte diameters were higher (P < 0.05) in the 50-ng/mL FSH treatment compared to the other groups after Day 7 of culture. Furthermore, estradiol secretion and ROS production were maintained (P > 0.05) throughout the culture in the 50-ng/mL FSH treatment. In conclusion, the addition of 50 ng/mL of FSH promoted activation of primordial follicles to developing follicles, improved survival of preantral follicles, and maintained estradiol and ROS production of equine ovarian tissue after 7 days of culture., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the effect of different combinations of insulin and FSH concentrations in culture media containing GH on the in vitro follicle morphology, antrum formation, growth rates, estradiol (E2) production, oocyte viability and maturation as well as gene expression for FSHR, GHR, INSR, CYP19A1, CYP17, 3ßHSD. Secondary follicles were individually cultured for 18 days in a basic medium containing 50ng/mL GH supplemented with low insulin concentration (INS-LW: 10ng/mL) or high insulin concentration (INS-HG: 10μg/mL) alone or with a fixed FSH concentration (FSH100: 100ng/mL) or with increasing FSH concentrations (FSH-SEQ: 100ng/mL, days 0-6; 500ng/mL, days 6-12; 1000ng/mL days 12-18). In the INS-LW treatment was observed a higher (P<0.05) incidence of normal follicles at day 18 of culture. However, overall higher (P<0.05) follicular growth, oocyte diameter and meiotic resumption rates were obtained using INS-HG+FSH 100. The INS-HG and INS-HG+FSH100 treatments showed higher E2 production and mRNA levels for CYP19A1, CYP17, 3βHSD when compared to INS-LW and INS-LW+FSH100. However, the addition of increasing FSH concentration, regardless of insulin concentration, did not improve the follicular growth, meotic resumption, E2 production or gene expression of steroidogenic enzymes when compared with INS-HG+FSH100. In conclusion, in presence of GH, a basic medium supplemented with 10μg/mL insulin and 100μg/mL FSH throughout the culture period, improves follicular and oocyte growth, oocyte meiotic resumption and E2 production from isolated preantral caprine follicles cultured in vitro., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Mannose is capable of decreasing bacterial attachment to the uterine mucosa in mares. Bacteria gain entry into the mare's uterus during breeding; therefore, a practical method to deliver mannose to the uterus is to incorporate it into semen extenders. The effect of mannose on spermatozoal motility and subsequent sperm fertilizing capability is unknown. The present study evaluated progressive spermatozoal motility in semen extender formulations incorporating mannose and assessed the fertility of mares inseminated with a mannose-containing semen extender. In Experiment 1, progressive spermatozoal motility in extender mixtures containing 0 mannose (control), 25, 37 or 49 mg/mL mannose was evaluated at 20 degrees C or 5 degrees C holding temperatures for 0, 12, 24 and 48 h post-dilution. Measures were repeated three times using five stallions of proven fertility. High concentrations of mannose in the extender affected progressive motility beyond the time and temperature effects noted in the controls. Extender containing only mannose sugar (49 mg/mL) displayed an immediate depression in progressive motility compared with controls (45.5% versus 62.9%, respectively; P<0.001). The 37 mg/mL mannose extender had a less dramatic decrease in motility (P<0.05) and only after storage at 5 degrees C for > or =12h (48.7% versus 58.0%, respectively). Extender with 25 mg/mL mannose performed no differently than the control formulation under all conditions. In Experiment 2, two groups of mares (n=11 each) were inseminated with 500 x 10(6) progressively motile spermatozoa extended in a traditional skim milk (control) extender or the 37 mg/mL mannose extender preparation. A single-cycle pregnancy rate of 72% was achieved by both groups. Present data suggest that a semen extender containing up to 37 mg/mL mannose could maintain motile spermatozoa for on-farm use and 25 mg/mL mannose concentrations preserved motility during long-term cooling. Likewise, sperm extended with up to 37 mg/mL of mannose had the same fertilizing capability as sperm in traditional extender mixtures.

Corn containing genetically engineered plasmid DNA encoding an Escherichia coli glutamate dehydrogenase (gdhA) was fed to 19-d-old weanling swine to trace the digestive fate of the transgenic DNA. Eight pens of 8 pigs were fed a commercial (nongdhA) starter for 2 wk. One pig was randomly selected from each pen for 0-h control samples. The remaining 56 pigs were transitioned onto a corn-soybean meal diet and fed a diet containing 58% gdhA corn for approximately 1 wk; immediately thereafter, liver, 10th rib muscle, white blood cells, and plasma from the hepatic portal vein and ingesta from the stomach, distal ileum, and large intestine were collected. The DNA was extracted and the concentration determined via spectrophotometry. Polymerase chain reaction and gel electrophoresis were performed with primers designed to amplify 490 bp that included the plasmid's ligation site between the maize ubiquitin and the gdhA genes. The gdhA corn-derived DNA and diet served as positive assay controls, and conventional corn DNA and distilled water acted as negative assay controls. Detection limits were 0.99 fg of target DNA confounded with 500 ng of conventional corn DNA per each 20 &L reaction. Transgenic DNA was detected in 71.43% of the stomach and 1.79% of the ileal ingesta samples from treatment animals but was not detected in the large intestine, white blood cells, plasma, liver, or muscle samples. Transgenic DNA was not detected in any sample from 0-h control animals. Stomach and ileal ingesta samples were further analyzed using real-time PCR. With an estimated limit of detection of 1.049 ag/microL, 89.29% of the stomach ingesta samples were positive (average 1.56 fg target DNA). The proportion of transgenic DNA to total DNA differed between diet and stomach ingesta samples (P < 0.001). Despite the greater sensitivity of real-time PCR, target DNA was detected in only 1.79% of ileal ingesta. These data suggest that the gdhA transgene began degradation in the stomach and was nondetectable in the large intestine.

Collection of ileal digesta to evaluate AA digestibilities has become increasingly important in swine nutrition research. Steered ileocecal valve cannulation of pigs permits total collection of ileal digesta, while still allowing normal digesta flow during noncollection periods. This technique was modified and used with 64 crossbred barrows in five trials. Our procedural changes included preoperative i.v. administration of a broad-spectrum antibiotic and nonsteroidal antiinflammatory drug, sharp incision through the muscle layers of the laparotomy wound, use of a heparinized saline lavage solution, replacement of the guide ring with a stylette, and fixing the outer cannula barrel in place with a hose clamp. The current technique involves a right flank laparotomy, parallel and distal to the last rib, with the pig under general anesthesia. A stainless-steel ring (inner ring = 2.0 mm thick, 35.0 mm i.d.) is introduced into the ileal lumen through an enterotomy proximal to the origin of the ileocecal fold. A nylon string attached to this ring is threaded through the ileum and ileocecal valve into the cecum using a silastic stylette, which encases the string. A second stainless-steel ring (outer ring = 2.0 mm thick, 34 mm o.d.) is fixed in place around the ileum, distal to the inner ring and just proximal to the ileocecal valve. A polyurethane cannula barrel (barrel = 100 mm long, 26 mm i.d., 32 mm o.d.; flange = 70 mm o.d.) is introduced into the cecal lumen via an enterotomy through the lateral cecal band and secured in place with two purse-string sutures. The cannula is exteriorized through an incision caudal and proximal to the intial laparotomy site, where it is plugged using a cylindrical stopper (26 mm o.d., 55 mm long) and held in place by a second cannula barrel (barrel = 43 mm length, 33 mm i.d., 41 mm o.d.; flange = 80 mm o.d.). Procedural changes decreased postsurgical complications, as evidenced by decreased seepage around the cannula and fewer and less severe adhesions noted at necropsy. Based on five trials, this technique is a reliable means of collecting ileal digesta for nutrient analyses.

Eight female PIC Line 42 pigs (initial BW = 47.5 +/- 1.8 kg) were used in a two-period switchback design (n = 4 per treatment per period) to evaluate the nutritional difference between a genetically modified corn and a similar nontransgenic corn. The genetically altered corn (gdhA+) contained a glutamate dehydrogenase gene isolated from Escherichia coli. The non-transgenic corn was the same variety lacking the transgenic cassette, grown at the same two locations. Pigs were surgically fitted with steered ileocecal valve cannulas for collection of ileal digesta. Diets were made up of primarily one of the two corn sources. Dietary AA profiles were adjusted using crystalline AA to match Illinois Ideal Protein Ratios. Pigs were limit-fed at 8% of metabolic body weight (BW0.75) in two equal feedings at 0600 and 1800 daily throughout the experiment. The study consisted of two 15-d periods. Each period consisted of a 7-d acclimation period, a 3-d total collection of feces and urine, two 12-h ileal collections, and a 3-d adjustment period between ileal collections to ensure adequate hydration. Crude protein, leucine, methionine, alanine, aspartic acid, glutamic acid, and tyrosine concentrations were greater (P < 0.05) in the gdhA+ corn than in the nontransgenic variety. The presence of the gene did not alter (P > 0.17) BW gain. Similarly, DM digestibility, fecal N excretion (grams per day), apparent total-tract N digestibility, N balance, net protein utilization, and N retained as percentages of absorbed were not affected (P > or = 0.32) by the gene modification. Apparent ileal AA digestibility values did not differ (P > 0.31) between the two dietary treatments. Results of this study suggest corn that contains the E coli. gene for glutamate dehydrogenase was nutritionally equivalent to the unaltered variety.

A steer finishing trial was performed to determine the effect of short-term dietary regimens on conjugated linoleic acid (CLA) content of muscle tissues. The experimental design was an incomplete 3 x 2 factorial, with three levels of soybean oil (SBO; 0, 4, and 8% of diet DM) and two levels of forage (20 vs. 40% of diet DM). Forty Angus x Hereford steers averaging 504 +/- 29.0 kg were allotted randomly to one of four treatments for the last 6 wk of the finishing period. Treatments were: 80:20 concentrate:forage control diet (C); 80:20 concentrate:forage + 4% SBO (C4); 60:40 concentrate:forage + 4% SBO (F4); and 60:40 concentrate:forage + 8% SBO (F8). After 42 d on the experimental diets, steers were sacrificed and samples were collected from the chuck, loin, and round muscle groups. Fatty acid (FA; mg/100 mg of FA) composition was determined by gas-liquid chromatography. Data were statistically analyzed with mixed models procedures. The performance and carcass quality model included the effects of SBO and forage. The model for FA composition included the effects of SBO, forage, muscle group, and interactions. Orthogonal contrasts were used to determine linear effects of SBO. There were no differences in growth performance among treatments (P > 0.05). Increasing dietary SBO linearly decreased dressing percent (P = 0.04), and tended to linearly decrease marbling score (P = 0.12) and quality grade (P = 0.08). The only CLA isomer detected in tissue samples was cis-9,trans-11. Addition of SBO to diets linearly increased linoleic acid (18:2n-6; P = 0.04) and tended to linearly increase linolenic acid (18:3n-3; P = 0.10) in muscle tissues. The CLA in lean tissues was decreased (P = 0.005) with SBO-containing diets. These findings suggest that increased PUFA may limit ruminal production of CLA and trans-vaccenic acid (VA) and/or may depress stearoyl-CoA desaturase expression or activity in lean tissues, which in turn limits CLA formation and accretion in tissues. Increasing dietary forage tended to increase 18:0, 18:2n-6, CLA, and 18:3n-3 (P < 0.15), suggesting that increased forage may mitigate toxic effects of PUFA on ruminal biohydrogenation, thereby increasing the pool of CLA and VA available for CLA formation and accretion in tissues. Short-term feeding of elevated SBO and forage levels can alter FA profiles in muscle tissues.

The effects of urea and rumen-degradable protein (RDP) on microbial growth, digestibility, and fermentation were examined using dual-flow continuous culture. The experimental design was a 4 x 4 Latin square with a 2 x 2 factorial arrangement of treatments. Factors were urea infusion (0.4 g/L of artificial saliva) and RDP concentration, and the treatments were as follows: 1) low RDP (8% of dietary dry matter) without urea (LDNU), 2) high RDP (11% of dietary dry matter) without urea (HDNU), 3) low RDP (8% of dietary dry matter) with urea (LDU), and 4) high RDP (11% of dietary dry matter) with urea (HDU). The LDNU (i.e., negative control) and HDNU treatments were formulated to be nitrogen limiting. Results indicated that infusion of urea increased all digestibility measurements (P < 0.05), which in turn increased (P < 0.05) volatile fatty acid, NH3 nitrogen, trichloroacetic acid-soluble nitrogen, and soluble protein concentrations. Increasing dietary RDP improved dry matter and organic matter digestibility (P < 0.05) but did not alter acid detergent fiber or nonfiber carbohydrate digestibilities (P > 0.05). Isobutyrate concentration decreased (P = 0.05) with increased RDP. Increased dietary RDP increased crude protein degradation and soluble protein concentration (P < 0.05), but NH3 nitrogen, trichloroacetic acid-soluble nitrogen, and peptide nitrogen were unaffected by changing RDP levels. Microbial growth efficiency was 19.9, 24.9, 28.0, and 32.2 g N/g organic matter truly digested for LDNU, HDNU, LDU, and HDU, respectively, and was significantly improved both by urea infusion (P = 0.002) and increased RDP concentration (P = 0.021). The interactions of urea and RDP (P < 0.05) were explained by the high digestibility of neutral detergent fiber, nonstructural carbohydrate, and especially hemicellulose, with the HDNU treatment. The results of this study indicated that hemicellulose-degrading bacteria were able to effectively compete with nonstructural carbohydrate-degrading bacteria for available peptide and amino acid nitrogen. Further, the extent of protein degradation was dependent on the availability of NH3 nitrogen in the system.

Twenty-four crossbred barrows (average BW, 70.8 kg) were used to compare the digestibility of dry matter and the mineral absorption and retention by pigs fed two Cu sources. Dietary treatments were 1) basal (B) (16% CP corn-soybean meal-based diet, 36 mg/kg of Cu), 2) B + 200 mg/kg of Cu from CuSO4.5 H2O (CuSO4), and 3) B + 200 mg/kg of Cu from a copper lysine complex (CuLys). All diets contained equal lysine content and .05% chromic oxide for indirect determination of absorption. Two 7-d total collection periods were conducted. Pigs were fed 8% of metabolic BW (BW.75) divided into two equal feedings. Average daily gain tended to be higher for pigs fed CuLys than for pigs fed CuSO4 (P < .02). Dry matter digestibilities were similar (P > .10) among treatments. The absolute amount of Cu absorbed and retained was greater for pigs fed both Cu sources (P < .001) than for pigs fed the control diet. Iron and Zn intake and excretion and the percentage of Fe absorbed and retained were similar (P > .10) among treatment groups. Chromium intake and excretion in feces were not different (P > .10), with an average recovery of 93.8%. Indirect DM digestibility was similar to total collection values; however, mineral values were similar only after correction for Cr recovery. Pigs fed elevated Cu absorbed more Cu, with no difference between the two sources. Zinc and Fe absorption and retention were generally not affected (P > .10) by Cu addition or sources. The absorption and retention of Cu was similar for pigs fed growth-stimulative levels of Cu from CuSO4 or copper lysine complex.

Two 5-wk trials using 176 weanling pigs (average initial weight of 8.3 kg and age of 31 d) were conducted to examine the effect of feeding varying levels of dietary Cu from copper sulfate (CuSO4) or a copper lysine complex (CuLys) on performance, mineral stores, serum copper, and serum mitogenic activity. Dietary treatments were 0 (15 mg/kg of Cu in basal diet), 100, 150, or 200 mg/kg of supplemental Cu from CuSO4 or CuLys. Average daily gain and ADFI increased linearly (P < .01) with increasing dietary levels of Cu during wk 1 to 2, 3 to 5, and 1 to 5, with no difference (P > .10) between the Cu sources. Overall gain:feed ratios were not consistently affected by Cu source. Dietary Cu linearly increased liver, kidney (P < .001), and brain (P < .05) concentrations of Cu. In the liver, the linear response to supplemental Cu differed between Cu sources (P < .001); pigs fed 200 mg/kg of Cu from CuLys had the highest concentration of Cu. Serum Cu concentrations increased linearly during wk 1 to 2 (P < .01), 3 to 5, and 1 to 5 (P < .001), with no difference (P > .10) between sources. Serum mitogenic activity increased linearly during wk 1 to 2 and 1 to 5 (P < .05). Growth performance was linearly improved as the dietary level of Cu increased from 15 to 200 mg/kg, with similar responses for both Cu sources. Serum and tissue concentrations of Cu were generally equally affected by the two Cu sources, except liver Cu concentration, which was onefold higher for pigs fed 200 mg/kg of Cu as CuLys.

Four trials using 312 weanling pigs (average initial weight, 7.2 kg) were conducted to examine the effect of Bifidobacterium globosum A (BGA) on the growth performance, scour scores, humoral and cell-mediated immune response, and pH and chloride ion concentration (CIC) of feces and gastrointestinal tract contents of pigs. Dietary treatments were 0, 5.0 x 10(4), 6.7 x 10(6), and 7.5 x 10(8) colony forming units (cfu) of BGA/d in Trial 1 and 0, 6.0 x 10(4), 5.0 x 10(5), and 5.0 x 10(6) cfu/d in Trials 2 through 4. Pigs fed the low or medium levels of supplemental BGA had a greater ADG (P < .05) than control pigs throughout Trial 1, whereas ADG was quadratically increased (P < .05) for the low or medium levels only during wk 3 to 5 for the pooled data for Trials 2, 3, and 4. The primary effect of dietary BGA additions on ADFI was a quadratic increase during wk 3 to 5 for Trial 1 (P < .05) and for the pooled data of Trials 2 through 4 (P < .10). Gain:feed ratios were generally unaffected by addition of BGA. Both ADFI and ADG tended to be decreased (P < .10) at the highest level of BGA in all trials. Scouring was not severe in any of the trials and was not consistently affected by feeding BGA. The pH and CIC of gastrointestinal contents or feces were not influenced by the feeding of BGA.(ABSTRACT TRUNCATED AT 250 WORDS)