Plasma Urea Nitrogen Concentrations Research Articles

Effects of High Ambient Temperature and Bypass Protein Supplementation on Performance of Crossbred Lambs

The objective of this experiment was to study the effect of dietary supplementation with a source ofbypass protein (cottonseed meal, CSM) on the performance of growing crossbred wethers fed lowdigestibility roughage at high ambient temperature. Sixteen unshorn Border Leicester x Merino lambsaged 6 months and weighing 24.90.37 kg were allocated into a 2x2 factorial design (2 diets and 2ambient temperatures). Each group was fed either wheaten chaff + 2% urea ad libitum or wheaten chaff +1% urea ad libitum + 100g/d cottonseed meal. The results show that respiration rate and rectal temperaturewere significantly affected by ambient temperature (P<0.01), but not by diet. Total dry matter intake wassignificantly higher (P<0.01) at lower temperature than at high temperature, and significantly higher(P=0.04) on the supplemented diet than on the control diet. Water intake tended (P=0.06) to be higher onthe CSM+ diet than on the control diet, and was significantly at greater (P<0.01) high ambient temperaturethan at low temperature. The concentration of NH3-N in the rumen fluid (ranged from 310±17 to 413±20mg N/L) did not differ significantly either between diets or ambient temperatures. Blood plasma ureanitrogen concentration was significantly higher in sheep on the control diet than in those on thesupplemented diet, and at low than high temperature. The organic matter digestibility was not significantlyaffected by temperature and diet. The rate of live weight gain was significantly (P<0.01) reduced by highambient temperature and the interaction between diet and temperature was significant (P<0.01). At lowtemperature, lambs on the supplemented diet grew significantly faster than those on the control diet, butnot at high temperature. In conclusion, high ambient temperature increases respiration rate, rectaltemperature and water intake but reduces dry matter intake and live weight gain. Supplementation with100 g/d of cottonseed meal could not outweigh the depressing effects of constant high ambienttemperature and humidity imposed in this experiment.

Effect of reduced energy density of close-up diets on metabolites, lipolysis and gluconeogenesis in Holstein cows.

ObjectiveAn experiment was conducted to determine the effect of reduced energy density of close-up diets on metabolites, lipolysis and gluconeogenesis in cows during the transition period.MethodsThirty-nine Holstein dry cows were blocked and assigned randomly to three groups, fed a high energy density diet (HD, 1.62 Mcal of net energy for lactation [NEL]/kg dry matter [DM]), a medium energy density diet (MD, 1.47 Mcal NEL/kg DM), or a low energy density diet (LD, 1.30 Mcal NEL/kg DM) prepartum; they were fed the same lactation diet to 28 days in milk (DIM). All the cows were housed in a free-stall barn and fed ad libitum.ResultsThe reduced energy density diets decreased the blood insulin concentration and increased nonesterified fatty acids (NEFA) concentration in the prepartum period (p<0.05). They also increased the concentrations of glucose, insulin and glucagon, and decreased the concentrations of NEFA and β-hydroxybutyrate during the first 2 weeks of lactation (p<0.05). The plasma urea nitrogen concentration of both prepartum and postpartum was not affected by dietary energy density (p>0.05). The dietary energy density had no effect on mRNA abundance of insulin receptors, leptin and peroxisome proliferator-activated receptor-γ in adipose tissue, and phosphoenolpyruvate carboxykinase, carnitine palmitoyltransferase-1 and peroxisome proliferator-activated receptor-α in liver during the transition period (p>0.05). The HD cows had higher mRNA abundance of hormone-sensitive lipase at 3 DIM compared with the MD cows and LD cows (p = 0.001). The mRNA abundance of hepatic pyruvate carboxykinase at 3 DIM tended to be increased by the reduced energy density of the close-up diets (p = 0.08).ConclusionThe reduced energy density diet prepartum was effective in controlling adipose tissue mobilization and improving the capacity of hepatic gluconeogenesis postpartum.

Evaluation of solubles syrup from microbially enhanced soy protein production as a supplement for growing dairy heifers

<h2>ABSTRACT</h2> The objective of this research was to conduct a preliminary study to determine whether solubles syrup from microbially enhanced soy protein production is viable as a supplement for growing dairy heifers. A 6-wk study with a randomized complete block design was conducted using 14 Holstein and 4 Brown Swiss heifers [310 ± 16.4 d of age; BW=337.6 ± 33 kg]. Treatments were (1) a control TMR (CON) and (2) a TMR with 6.5% microbially enhanced soy protein solubles syrup (DM basis) in partial replacement of soybean meal and corn (SYP). Both diets contained similar inclusion rates of corn silage, grass hay, and mineral mix and were balanced to be comparable in CP and energy. Heifers were fed for ad libitum intakes using a Calan gate feeding system. Frame sizes, BW, and BCS were measured every 2 wk of the feeding period, and coccygeal blood samples and rumen fluid, sampled via esophageal tube, were collected every 2 wk at 4 h after feeding. Fecal grab samples were collected in wk 6. Dry matter intake, BW, and ADG were similar between treatments. Frame measurements and BCS were similar. Rumen fermentation profiles were similar; however, ammonia-nitrogen was greater for CON. Plasma urea nitrogen concentration was greater for CON; all other blood metabolites were similar. The SYP treatment had greater NDF, DM, and OM total-tract digestibility, and there was a tendency for increased CP and ADF digestibility. Results indicate that there is potential for solubles syrup from microbially enhanced soy protein production as a protein replacement in growing heifer diets.

Tear glucose, creatinine, and urea nitrogen concentrations in cats with normal or increased plasma concentrations.

The aim of the study was to determine the lacrimal fluid (LF) contents of glucose, urea nitrogen, and creatinine in cats. A total of 96 cats were included in the study. Venous blood and LF samples were collected. For LF sampling, three small polyurethane sponges were placed in the ventral fornix of both eyes. Both LF and plasma concentrations of glucose, urea nitrogen, and creatinine were quantitatively analyzed and compared. Glucose (n = 40) and urea nitrogen concentrations (n = 42) measured in LF from both eyes highly correlated. While there was a very strong correlation (ρ = 0.97) between urea nitrogen concentrations in blood plasma and the corresponding tear levels (with the median LF urea nitrogen being 109% of that measured in plasma), the LF glucose concentrations were significantly lower than the corresponding plasma concentrations (with only 13% of the blood glucose concentration detected in the LF). The creatinine concentrations in tears were much lower than those in plasma, and LF creatinine was detectable in only 12/48 cats (25%). Hence, a comparison of the LF creatinine concentrations between both eyes or with the corresponding plasma creatinine concentration was not possible. Measurement of LF urea nitrogen concentrations in cats appears to be reliable and might have potential clinical utility. Measurement of LF glucose concentrations is less reliable but may still be useful in some cats. Creatinine is not reliably detected in the LF in cats. Further studies determining clinical utility of LF metabolites in cats and other companion animals are warranted.

Blood Biochemical Profile in Fertile and Repeat Breeder Ongole Cross Breed Cows.

Repeat breeding is a major problem in beef cows. The objective of the present study was to determine the blood biochemical levels in repeat breeder and fertile Ongole cross breed cows. This study compared the blood biochemical profiles from 30 repeat breeders and 30 fertile Ongole cross breed cows. Plasma glucose, total cholesterol, total protein and urea nitrogen concentrations were examined in repeat breeder cows and compared with those of fertile cows. Blood samples were collected from the caudal vein into anticoagulant-coated tubes. Cells were removed from plasma by centrifugation and blood glucose, total cholesterol and urea nitrogen concentrations were measured using commercially available kits; a non-commercial kit was used to determine total protein content. Significantly different blood profiles between repeat breeder and fertile cows were reported. Specifically, repeat breeder cows had lower levels of glucose, total cholesterol and total protein, but higher levels of urea nitrogen than fertile cows. Finally, a low level of total protein, total cholesterol and glucose, accompanied by a high level of urea nitrogen, may cause reproductive problems in repeat breeders. Additionally, present findings indicated that biochemical blood profiling could be used as a diagnostic tool for repeat breeding.

Energy balance affects pulsatile secretion of luteinizing hormone from the adenohypophesis and expression of neurokinin B in the hypothalamus of ovariectomized gilts.

The pubertal transition of gonadotropin secretion in pigs is metabolically gated. Kisspeptin (KISS1) and neurokinin B (NKB) are coexpressed in neurons within the arcuate nucleus of the hypothalamus (ARC) and are thought to play an important role in the integration of nutrition and metabolic state with the reproductive neuroendocrine axis. The hypothesis that circulating concentrations of luteinizing hormone (LH) and expression of KISS1 and tachykinin 3(TAC3, encodes NKB) in the ARC of female pigs are reduced with negative energy balance was tested using ovariectomized, prepubertal gilts fed to either gain or lose body weight. Restricted feeding of ovariectomized gilts caused a rapid and sustained metabolic response characterized by reduced concentrations of plasma urea nitrogen, insulin, leptin, and insulin-like growth factor-1 and elevated concentrations of free fatty acids. The secretory pattern of LH shifted from one of low amplitude to one of high amplitude, which caused overall circulating concentrations of LH to be greater in restricted gilts. Nutrient-restricted gilts had greater expression of follicle-stimulating hormone and gonadotropin-releasing hormone receptor, but not LH in the anterior pituitary gland. Expression of KISS1 in the ARC was not affected by dietary treatment, but expression of TAC3 was greater in restricted gilts. These data are consistent with the idea that hypothalamic expression of KISS1 is correlated with the number of LH pulse in pig, and further indicate that amplitude of LH pulses may be regulated by NKB in the gilt.

Relationship between indirect blood pressure and various stages of chronic kidney disease in cats.

Chronic kidney disease (CKD) is a common cause of secondary systemic hypertension in cats. We investigated the relationship between indirect blood pressure and the prevalence of systemic hypertension in various CKD stages in cats. Client-owned cats (24 control cats and 77 cats with CKD) were included. Biochemical examinations of plasma were conducted by a commercial laboratory. Diseased cats were divided into two groups based on the International Renal Interest Society (IRIS) guidelines (II and III–IV). Indirect blood pressure was measured using an oscillometric technique. Severe hypertension was diagnosed if systolic blood pressure (SBP) was ≥180 mmHg. Indirect blood pressures were significantly higher in IRIS stage III–IV than in the control cats. Of 77 cats with CKD, 25 (32.5%) had severe hypertension. The frequency of severe hypertension increased with an increase in IRIS stage; 0% in the controls, 27.6% in the IRIS stage II, and 47.4% in the IRIS stage III–IV, respectively. The indirect SBP was weakly correlated with urea nitrogen (r=0.27) and creatinine (r=0.23) concentrations in plasma. Binary logistic regression analysis showed that if plasma creatinine concentration is >3.7 mg/dl, cats with CKD had an increased risk for developing severe hypertension (P<0.001). Our results suggest that indirect blood pressure was correlated with the severity of CKD, and the prevalence of severe hypertension increased in cats with severe CKD. The risk of severe hypertension may be high in cats with severe CKD.

Interaction between supplemental zinc oxide and zilpaterol hydrochloride on growth performance, carcass traits, and blood metabolites in feedlot steers.

Interactive effects of supplemental Zn and zilpaterol hydrochloride (ZH) were evaluated in feedlot steers ( = 40; 652 kg ± 14 initial BW) to determine their impact on feedlot performance, blood constituents, and carcass traits. The study was conducted as a randomized complete block design with a 2 × 2 factorial treatment arrangement. Steers were blocked by BW and randomly assigned to treatments. Factors consisted of supplemental Zn (60 or 300 mg/kg diet DM) and ZH (0 or 8.33 mg/kg) in the diets. For diets supplemented with 300 mg Zn/kg DM, 60 mg Zn/kg was supplemented as zinc sulfate and 240 mg Zn/kg was supplemented as zinc oxide, and the diet was fed for 24 d. Zilpaterol hydrochloride was fed for 21 d followed by a 3-d withdrawal. Cattle were housed in partially covered individual feeding pens equipped with automatic waterers and fence-line feed bunks and were fed once daily for ad libitum intake. Plasma samples were collected on d 0 and 21 to assess changes in Zn, plasma urea nitrogen (PUN), glucose, and lactate concentrations, and serum samples were collected on d 21 to assess IGF-1 concentration. On d 25, cattle were weighed and transported 450 km to a commercial abattoir for harvest; HCW and incidence of liver abscesses were recorded. Carcass data were collected after 36 h of refrigeration. Data were analyzed as a mixed model with Zn, ZH, and Zn × ZH as fixed effects; block as a random effect; and steer as the experimental unit. No interaction or effects of Zn or ZH were observed for IGF-1 concentration, plasma glucose, or lactate concentrations ( ≥ 0.25). No interaction between Zn and ZH was observed for PUN concentration, but PUN decreased with ZH ( < 0.01). There were no effects of ZH or Zn on ADG, DMI, final BW, feed efficiency, HCW, back fat, KPH, quality grade, or incidence of liver abscesses ( > 0.05). Zinc supplementation tended ( = 0.08) to improve the proportion of carcasses grading USDA Choice. Feeding ZH decreased yield grade ( = 0.05) and tended to increase LM area ( = 0.07). In conclusion, increasing dietary concentrations of Zn does not impact response to ZH, but feeding ZH altered circulating concentrations of PUN.

Growth performance, rumen fermentation, nutrient utilization, and metabolic profile of dairy heifers limit-fed distillers dried grains with ad libitum forage

The objective of this study was to determine the effects of feeding a corn- and soybean-product-based concentrate mix or distillers dried grains with solubles concentrate mix with ad libitum grass hay to dairy heifers. A 16-wk randomized complete block design study was conducted using 24 heifers [18 Holstein and 6 Brown Swiss; 219 ± 2 d of age (±standard deviation); 230 ± 4 kg of body weight] to evaluate the effect of diet on dry matter intake (DMI), growth performance, rumen fermentation, metabolic profile, and nutrient digestibility. Treatments were (1) corn and soybean product concentrate mix, and (2) distillers-dried-grains-with-solubles-based concentrate mix (DDG). Both concentrate mixes were limit-fed at 0.8% of body weight and grass hay was offered ad libitum. Heifers were individually fed using Calan gates and orts were recorded daily at feeding. Heifers were weighed every 2 wk and ration concentrate mix offered was adjusted accordingly. Frame measurements and body condition score were recorded every 2 wk. Rumen fluid was collected via esophageal tubing during wk 12 and 16 for pH, ammonia N, and volatile fatty acid analysis. Jugular blood samples were collected every 4 wk for metabolite and metabolic hormone analysis. Total-tract digestibility of nutrients was evaluated during wk 16 by fecal grab sampling. No treatment by week interactions were observed for any of the growth measurements and growth measurements and DMI did not differ between treatments. A treatment by time interaction was observed for rumen butyrate percentage with heifers fed DDG having a greater percentage. Total volatile fatty acid concentration, acetate molar percentage, and acetate:propionate decreased with the DDG treatment, whereas propionate molar percentage increased. No treatment by week interactions were observed for any of the metabolites or metabolic hormones measured. A tendency was observed for glucose and plasma urea nitrogen concentration to decrease with DDG. Plasma cholesterol and insulin increased with DDG. Results demonstrated that limit-feeding heifers DDG at 0.8% of body weight with ad libitum grass hay maintained growth performance, average daily gain, DMI, and gain:feed, with shifts in the metabolic profile compared with the corn and soybean product concentrate mix.

Interactive effects of supplemental Zn sulfate and ractopamine hydrochloride on growth performance, carcass traits, and plasma urea nitrogen in feedlot heifers.

Interactive effects of supplemental Zn and ractopamine hydrochloride (RH) were evaluated using 156 crossbred heifers (initial BW = 527 kg ± 6.61; gross BW × 0.96) to determine the impact on feedlot performance, plasma urea nitrogen (PUN), and carcass characteristics. The study was conducted as a randomized complete block design with a 2 × 2 factorial arrangement of treatments. Factors consisted of 1) 30 or 100 mg supplemental Zn/kg diet DM (30Zn or 100Zn) as Zn sulfate and 2) 0 or 200 mg RH/heifer daily. Heifers were blocked by BW and assigned randomly within block to treatments for a 43-d trial. Heifers were housed in partially covered feeding pens (3 heifers/pen; 13 pens/treatment) and provided ad libitum access to feed. Ractopamine hydrochloride was fed for 42 d and removed from the diet until cattle were harvested on d 43. Zinc treatments were fed until harvest. Plasma samples were collected on d 0 and 36 to assess changes in plasma Zn and PUN. On d 43, heifers were weighed, then transported to a commercial abattoir where HCW and incidence of liver abscesses were recorded. Carcass data were collected after 32 h of refrigeration. No Zn × RH interactions were observed for plasma Zn or PUN ( ≥ 0.58); however, there was a tendency for a RH × day interaction for PUN ( = 0.08). Supplementing 100Zn resulted in increased plasma Zn ( = 0.02) compared to 30Zn. No RH × Zn interactions were observed for feedlot performance ( ≥ 0.24). Final BW and ADG increased with RH supplementation ( ≤ 0.02), but DMI was not affected ( = 0.63); thus, feed efficiency improved ( < 0.01) when heifers were fed RH. Supplementing 100Zn tended to reduce ADG ( = 0.07) but did not affect other measures of feedlot performance ( ≥ 0.12). Zinc × RH interactions were observed for LM area and yield grade ( ≤ 0.01); LM area decreased and yield grade increased when heifers were supplemented 100Zn with no RH compared to other treatments. A tendency for a Zn × RH interaction was observed for dressed yield ( = 0.08), but no other interactions or effects of Zn were detected for carcass traits ( ≥ 0.11). Supplementing RH increased HCW ( = 0.03) but did not affect other carcass traits ( ≥ 0.13). In conclusion, supplemental Zn had little impact on feedlot performance or PUN concentration but may alter muscle and fat deposition when fed in conjunction with RH.

Changes in faecal bacteria during fattening in finishing swine

Body fat accumulation in mice and human is linked to the percentage of Firmicutes and Bacteroidetes, two bacterial phyla dominant in the large intestine. However, little is known about the relationship between the composition of the gut microbiota and fattening in pig. This study aimed to investigate the abundance of Firmicutes, Bacteroidetes, and Bacteroides, which is the major genus within Bacteroidetes, in porcine faeces during fattening. Ten 4-month-old crossbred pigs were given free access to commercial feed for fattening and water for 14 weeks. Daily feed intake and body weight were measured every 2 weeks. Faecal samples were collected at 0, 4, 8, and 14 weeks, and plasma samples were collected every 2 weeks. Daily feed intake increased until 8 weeks, and then decreased. Body weight increased with fattening during the experimental period. Feed efficiency showed high values at 0–4 and 6–8 weeks. The level of Firmicutes increased (P < 0.05), whereas those of Bacteroides and Bacteroidetes decreased (P < 0.05) with fattening. The total short chain fatty acid content in the faeces increased (P < 0.05) with fattening until 8 weeks and then decreased (P < 0.05) at 14 weeks. There were no significant relationships between the level of Firmicutes and feed intake or plasma leptin concentration. The levels of Bacteroidetes and Bacteroides correlated with feed intake, body weight, and plasma leptin or plasma urea nitrogen (PUN) concentration. Our results suggested that the level of Firmicutes increased and those of Bacteroidetes and Bacteroides decreased with increase in feed intake and body weight, similar to previous results obtained for mice and human. However, energy extraction from feed was not influenced by compositional alteration of gut flora, because daily gain and feed efficiency did not show high values towards the end of the fattening period. Manipulating the gut microbiota might help improve fattening performance, although further studies are necessary to understand the relationships between the composition of gut microbiota and energy absorption.

Effects of dietary lysine levels on the concentrations of selected nutrient metabolites in blood plasma of late‐stage finishing pigs

Lysine is the first-limiting amino acid (AA) in typical swine diets and plays very important roles in promoting growth performance of pigs. This research was conducted to study the effects of dietary lysine on blood plasma concentrations of protein, carbohydrate, and lipid metabolites of pigs. Eighteen crossbred finishing pigs (nine barrows and nine gilts; initial BW 92.3±6.9kg) were individually penned in an environment controlled barn. Pigs were assigned to three dietary treatments according to a randomized complete block design with gender as block and pig as experimental unit (6 pigs/treatment). Three corn and soybean meal-based diets were formulated to contain total lysine at 0.43%, 0.71%, and 0.98% (as-fed basis) for Diets I (lysine deficient), II (lysine adequate), and III (lysine excess) respectively. After 4weeks on trial, jugular vein blood was collected and plasma was separated. The plasma concentrations of total protein, albumin, urea nitrogen (UN), triglyceride, total cholesterol, and glucose were determined using an ACE Clinical Chemistry System (Alfa Wassermann, Inc., West Caldwell, NJ, USA). Data were analysed using the GLM Procedure with PDIFF (adjust=T) option of SAS. No differences (p>0.10) were found between barrows and gilts for any of the metabolites measured. While there were no differences (p>0.10) between pigs fed Diets II and III in plasma concentrations of UN, albumin, and total cholesterol, the concentration of albumin in these pigs was higher (p<.05) than that of pigs fed Diet I, and the concentrations of UN and total cholesterol in these pigs were lower (p<.05) than that of pigs fed Diet I. There were no differences (p>0.10) among the three dietary treatments in plasma concentrations of total protein, triglycerides, and glucose. These findings indicated that the plasma metabolite profile can be affected by changing dietary lysine content only. Thorough understanding how the plasma metabolite profile is alternated by dietary lysine will facilitate nutrient management for more sustainable swine production.

The addition of protein-bound amino acids in low-protein diets improves the metabolic and immunological characteristics in fifteen- to thirty-five-kg pigs.

This study was to evaluate the effects of supplementation of AA form (crystalline vs. protein bound) in low-protein diets on growth, metabolic, and immunological characteristics of pigs. A total of 80 barrows (PIC 327 × 1050; 15.57 ± 0.13 kg BW and 48 ± 2 d of age), housed in 4 pigs per pen with 5 pens per treatment, were assigned to 4 dietary treatments of 17, 15, and 13% CP and 13% CP plus casein for 28 d. The crystalline AA were supplemented to meet the requirement of indispensable AA in pigs. Results showed that pigs fed the 13% CP diet or the 13% CP plus casein diet had lower ( < 0.01) ADG and ADFI and a greater ( < 0.01) feed:gain ratio than pigs fed the 17% CP or 15% CP diets over the 4-wk study period. Compared with other diets, pigs fed the 13% CP diet had decreased concentrations of plasma urea nitrogen, albumin ( < 0.01), and mRNA expressions of Toll-like receptor 4 (), nuclear factor kappa B (; < 0.05), and Toll-interacting protein (; < 0.01) in the ileum and also increased activity of plasma glutamate-pyruvate transaminase ( < 0.05) and concentrations of IL-1β ( < 0.05) and tumor necrosis factor-α ( < 0.01); however, these characteristics were partly normalized by feeding the 13% CP plus casein diet. Furthermore, the plasma concentration of insulin-like growth factor 1 (IGF-1; < 0.01) and mRNA expressions of protein kinase B (), mammalian target of rapamycin (), and ribosomal protein S6 kinase () in longissimus muscle were increased ( < 0.05) in pigs fed the 13% CP plus casein diet relative to pigs fed the 17% CP or 15% CP diets. In summary, reducing dietary CP level from 17% to 15% had no effect on growth, metabolic, and immunological characteristics of 15- to 35-kg pigs. A further reduction of dietary CP level up to 13% would lead to poor growth performance, but metabolic and immunological characteristics were partly normalized using protein-bound AA to replace synthesized AA in the 13% CP diet.

Dietary arginine supplementation in multiparous sows during lactation improves the weight gain of suckling piglets

This study investigated the effects of dietary arginine (Arg) supplementation, just during lactation, on sow and litter performance, plasma concentrations of metabolites and hormones, and milk yield and composition in multiparous sows. Thirty-one sows were randomly assigned to 3 dietary treatments supplemented with 0.0 (control, n=10), 0.5% (n=10), or 1.0% (n=11) L-Arg-HCI, respectively. Experimental diets were provided to the sows from d 3 to 21 of lactation. Plasma and milk samples were collected at d 14 and 21 of lactation. The average daily gain (ADG) of piglets from sows fed diets supplemented with 0.5 or 1.0% L-Arg-HCI at d 3 to 14 of lactation, were higher than that of controls (P<0.05). Maternal supplementation with 1.0% L-Arg-HCI also increased ADG of piglets between d 3 and 21 of lactation than that of the controls (P<0.05). There was no significant effect of supplementation on average daily feed intake (ADFI), body weight loss, and backfat thickness loss of lactating sows. Supplementation with 0.5 or 1.0% L-Arg-HCI had a trend towards increasing milk yields and milk fat contents (0.05<P<0.10); milk protein and lactose were unchanged. Supplementation with 1.0% L-Arg-HCI increased plasma concentrations of prolactin and insulin in sows at d 14 and 21 of lactation, and plasma concentrations of non-esterified fatty acid (NEFA), insulin-like growth factor-1 (IGF-1), and nitric oxide (NO) in sows at d 21 of lactation, when compared to the controls (P<0.05). Supplementation with 1.0% L-Arg-HCI increased IGF-1 and spermine in milk at d 14 of lactation, relative to the controls (P<0.05). Plasma Arg concentrations at d 14 and 21 of lactation, as well as plasma NO level and milk IGF-1 at d 21 of lactation, were increased, while plasma urea nitrogen (PUN) concentration at d 14 and 21 of lactation was decreased, by supplementation with 0.5 or 1.0% L-Arg-HCI when compared to the controls (P<0.05). Collectively, dietary supplementation of multiparous sows with Arg, just during lactation, is beneficial for enhancing litter weight gain but the complete mechanism remains to be determined and may involve in the maternal endocrine changes and milk polyamines contents.

Effects of cinnamaldehyde or monensin on performance of weaned Holstein dairy heifers

The objective of this 70-d study was to determine the effects of the essential oil cinnamaldehyde compared with the ionophore monensin on performance of weaned Holstein dairy heifers. Eighty-four Holstein dairy heifers (91 ± 3.33 d of age; 109 ± 7.55 kg) were housed in a naturally ventilated curtain sidewall, straw-bedded barn in 12 pens with 7 heifers/pen (3.98 m2/head). Heifers were randomly assigned to 1 of 4 treatments in a completely randomized design: (1) control (CON; carrier, 908 g of ground corn), (2) monensin sodium [MON; 1 mg/kg of body weight (BW) + carrier], (3) cinnamaldehyde (CIN1; 1 mg/kg of BW + carrier), or (4) cinnamaldehyde (CIN2; 2 mg/kg of BW + carrier). The treatments were hand-mixed into a 20% crude protein (CP) whole shelled corn and protein pellet mix fed at 2.21 kg/heifer daily. Heifers had access to free-choice hay and water daily. Initial BW and hip heights were taken at the start of the study and every other week thereafter until calves reached 23 wk of age. Blood samples were also taken on each weigh day to determine plasma urea nitrogen, glucose, and insulin-like growth factor-1 concentrations. Fecal samples were taken from the same 3 heifers/pen initially and then at d 28, 56, and 70 of the study for coccidia counts. Cinnamaldehyde had no performance effects on growth, hay intake, hip height, or blood metabolites compared with MON or CON. Average daily gains were 0.98, 0.99, 1.01, and 1.03 kg/d, and average hay intakes per pen were 17.08, 16.34, 18.11, and 17.60 kg/d for CON, MON, CIN1, and CIN2, respectively. Fecal samples by pens indicated the presence of viable coccidia, but the counts were low and not consistent across heifers within each pen. No benefits were associated with supplementing cinnamaldehyde or monensin into grain mixes for weaned heifers.

Effects of different dietary tryptophan:lysine ratios and sanitary conditions on growth performance, plasma urea nitrogen, serum haptoglobin and ileal histomorphology of weaned pigs.

A total of 180 mixed-sex pigs (Duroc × (Yorkshire × Landrace); average initial body weight of 7.36±0.2kg) weaned at 21±1 days were fed corn-soybean meal-wheat-based diets to determine the optimal standardized ileal digestible (SID) tryptophan to lysine ratio (Trp:Lys) in a 2×5 factorial arrangement (two sanitary conditions: clean (CL) and unclean (UCL), and five dietary treatments (SID Trp:Lys (16, 18, 20, 22 and 24%)). In each sanitary condition, blood was collected on days 0 and 14 to determine plasma urea nitrogen and on day 14, ileal tissue (one pig per pen) was collected for the measurement of gut morphology. Pigs kept under UCL conditions had lower growth rate (P<0.05) than under CL conditions. Under CL conditions, the estimated optimal SID Trp:Lys for average daily gain (ADG) was 19.7% whereas under UCL conditions these values were 20.5% and 19.0% for ADG and gain-to-feed ratio, respectively. Under CL conditions, increasing SID Trp:Lys reduced (linear, P=0.05) plasma urea nitrogen concentration but had no effect (P>0.10) on villous height (VH), crypt depth ( CD) and VH:CD. In conclusion, an SID Trp:Lys to optimize ADG for pigs raised under UCL conditions was higher (4%) than CL conditions.

Effect of heme oxygenase-1 transduced by cell penetrating peptide PEP-1 on renal injury in rats with acute paraquat poisoning

Objective: To study the effects of heme oxygenase-1 transduced by cell penetrating peptide PEP-1 on renal injury in acute paraquat-induced rats. Methods: The fusion protein PEP-1/HO-1 was manufactured by genetic engineering methods. One hundred and twenty-six healthy adult Sprague-Dawley (SD) rats (63 male, 63 female) were randomly divided into three groups: (1) Control group: 42 rats, (2) Poisoned group: 42 rats, (3) PEP-1/HO-1 intervention group: 42 rats. The rats in Poisoned group and intervention group were treated intraperitoneally with paraquat (25 mg/kg) deliquated with normal saline. Control group rats were treated with the same way of normal saline as the others. Intervention group rats were injected 1 mg of the fusion protein PEP-1/HO-1 into the left iliac vein at 30 minutes before the administration of the paraquat. After abdominal dissection with ether anaesthesia, six rats respectively from each of three groups were taken tissue samples from kidney at 1 st、6 th、12 th、24 th、36 th、48 th、and 72 nd hour respectively. Tissue Superoxide Dismutase (SOD) activity and Malondialdehyde (MDA) content were measured, and renal tissue was quickly remained to observe the expression of Heme Oxygenase-1 (HO-1) by the method of immunohistochemistry. Blood samples were collected from the abdominal aorta for determination of Blood Urea Nitrogen (BUN) and Creatinine (Cr) concentrations in plasma. Results: To prepare high purity fusion protein PEP-1/HO-1 Successfully. The levels of the plasma Bun and Cr in Poisoned and intervention group were significantly higher than that in Control group in the six to seventy-two hours (P<0.01) ; Whereas the increases of Bun and Cr were markedly intibited in PEP-1/HO-1 intervention group, in which, the levels of Bun and Cr in the six to seventy-two hours were significantly lower than Poisoned group (P<0.05). Compared with control group, the levels of MDA in poisoned groups were increased in the one to forty-eight hours and the levels of it in groups PEP-1/HO-1 in the one to thirty-six (P<0.01 or P<0.05). The T-SOD activity of the poisoned group was decreased in the one to thirty-six hours than that of the control group (P<0.05). Compared with poisoned group, the T-SOD activity at various points in time was increased in group PEP-1/HO-1 (P<0.01). In control group, there was only very weak expressions of HO-1 in the normal renal tissue. In poisoned and intervention group, the expressions of HO-1 were significantly higher than that in control group in all time (P<0.01). The HO-1 expressions of PEP-1/HO-1 group in all time was significantly higher than that in poisoned group (P<0.01 or P<0.05). Conclusion: The HO-1 protein Can be successfully transduced into renal tissue by cell penetrating peptide PEP-1 and the transduced HO-1 protein reduces renal injury of the acute paraquat-induced rats by inhibiting lipid peroxidation response.

Uterine environment and pregnancy rate of heifers with elevated plasma urea nitrogen

Diets high in protein are associated with lower reproductive performance and changes in the uterine environment. The objective of this study was to determine the effect of elevated systemic concentrations of urea nitrogen on the uterine environment and pregnancy success in beef heifers. Heifers (n=150) were matched by breed, age, and body weight then randomly assigned to one of two dietary treatments: 1) Control (10% CP) or 2) High protein (14% CP) over three replicates (n=40/replicate). Estrus was synchronized with an injection of PGF2α. Uterine pH, plasma urea nitrogen (PUN), ammonia, and glucose concentrations were determined on d 7 of the estrous cycle. Pregnancy status was determined by ultrasonography 30 d following the breeding season. In vitro fertilization was performed on heifers precluded from uterine analysis (n=15/diet) to determine the effect of a High Protein diet on oocyte quality. Plasma urea concentrations were greater in the High Protein diet compared to Control (P<0.001). There was no effect of diet on plasma ammonia (P=0.12), plasma glucose (P=0.40), uterine pH (P=0.67), interval to estrus (P=0.54), duration of estrus (P=0.38), or pregnancy rate (P=0.83). There was no effect of diet (P>0.40) on the number of oocytes collected, number of oocytes cleaved, amount of blastocysts, percentage of oocytes cleaved and percentage of blastocysts present. In summary, high nitrogen diets increased PUN concentrations in heifers; however, there were no deleterious effects on reproduction.

Standardized ileal digestible lysine requirements of male pigs immunized against gonadotrophin releasing factor.

An experiment was conducted to determine the standardized ileal digestible (SID) Lys requirement of entire male and male pigs immunized against gonadotrophin releasing factor (GnRF; immunocastrates). A total of 420 entire male and immunocastrated (IC) male pigs weighing 60.1 kg BW (SEM 0.49) were used in a 2 × 5 factorial experiment with the main effects being gender (entire males or IC males) and 5 concentrations of SID Lys:DE ratio (0.32, 0.43, 0.54, 0.64, or 0.75 g SID Lys/MJ DE). The diets were fed for 6 wk until slaughter at 107.5 kg BW (SEM 5.72). Over the entire period, IC males had a greater ADG ( < 0.001), greater ADFI ( < 0.001), and lower G:F ( < 0.001) compared with entire males. Immunocastrated males had increased plasma urea nitrogen (PUN) concentrations compared with entire males from d 10 to 42 ( < 0.001 for all days). Plasma urea nitrogen concentration also increased as Lys concentrations increased from d 3 to 42 ( < 0.001 for all days). Using the linear-plateau model, the optimal ADG for entire males was achieved at SID Lys concentrations of 0.68, 0.62, 0.54, and 0.58 g/MJ DE whereas optimal G:F was achieved at SID Lys concentrations of 0.72, 0.60, 0.54, and 0.51 g/MJ DE for the time periods d 0 to 14, d 15 to 28, d 29 to 42, and d 0 to 42, respectively. For IC males, optimal ADG was achieved at SID Lys concentrations of 0.64, 0.43, 0.38, and 0.40 g/MJ DE whereas optimal G:F was achieved at SID Lys concentrations of 0.64, 0.43, 0.36, and 0.42 g/MJ DE for the same respective time periods. Using the quadratic polynomial model, maximum ADG for entire males was achieved at SID Lys concentrations of 0.62 and 0.58 g/MJ DE whereas maximum G:F was achieved at SID Lys concentrations of 0.59 and 0.68 g/MJ DE for d 29 to 42 and d 0 to 42, respectively. For IC pigs, maximum ADG was achieved at SID Lys concentrations of 0.69, 0.54, and 0.64 g/MJ DE whereas maximum G:F was achieved at SID Lys concentrations of 0.81, 0.54, and 0.64 g/MJ DE for d 0 to 14, d 29 to 42, and d 0 to 42, respectively. A solution could not be found using the quadratic polynomial model for entire males for d 0 to 14 for both ADG and G:F and for both entire males and IC males for d 15 to 28 within the range of Lys values tested. When both the growth performance and PUN values are considered, the results suggest that IC males show a response to dietary SID Lys similar to that of entire males for 2 wk after the second immunization against GnRF. After this, IC males have a lower requirement for SID Lys than entire males.

Influence of milk urea concentration on fractional urea disappearance rate from milk to blood plasma in dairy cows

The relationship between milk urea nitrogen (MUN; mg of N/dL) and urinary N excretion is affected, among others, by diurnal dynamics in MUN, which in turn is largely influenced by feed intake pattern and characteristics of urea transfer from blood plasma to milk and vice versa. This study aimed to obtain insight in urea transfer characteristics within the mammary gland and from the mammary gland to blood plasma in dairy cows at various concentrations of plasma urea nitrogen (PUN; mg of N/dL) and MUN. Urea transfer from milk to blood plasma and urea transfer within the mammary gland itself was evaluated in a 4×4 Latin square design using 4 lactating multiparous Holstein-Friesian cows (milk production of 39.8±4.70kg/d and 90±3.9 d in milk). Treatments consisted of 4 primed continuous intravenous urea infusions of 0, 5, 10, and 15g of urea/h. Boluses of [15N15N]urea were injected in cistern milk at 20, 60, and 100 min before the 1700h milking. Milk was collected in portions of approximately 2 L at the 1700h milking. Milk samples were analyzed for urea and enrichment of 15N-urea. Results from one cow were discarded because of leakage of milk from the teats after injection of boluses of [15N15N]urea. Increasing urea infusion rate linearly increased PUN from 11.4 (0g of urea/h) to 25.9mg/dL (15g of urea/h) and MUN from 10.3 (0g of urea/h) to 23.5 (15g of urea/h) mg of N/dL. The percentage of injected [15N15N]urea recovered from milk at the time of injection was not affected by urea infusion rate and varied between 65.1 and 73.0%, indicating that a substantial portion of injected [15N15N]urea was not accounted for by collected milk. The estimated fractional disappearance rate of 15N-urea from milk to blood (Kurea; per hour) linearly increased from 0.429 (0g of urea/h) to 0.641 per hour (15g of urea/h). Cistern injected [15N15N]urea diffused within 20 min after injection toward alveoli milk. Calculations with the average Kurea estimated in this study show that 89% of an initial difference between PUN and MUN will have disappeared after 4 h. In conclusion, urea disappearance from milk in the mammary gland is substantial, as well as the intramammary urea exchange between cistern, duct, and alveoli milk. However, results have to be interpreted with caution given the lack of full recovery of dosed 15N urea at time of injection. Information on Kurea is useful to quantify the effects of diurnal variation in PUN on MUN, which enhances the utility of MUN as an indicator for N excretion in urine.