Nutrient utilization in lambs fed diets high in sodium or potassium

Twenty-four wether lambs averaging 47 kg were used to study the effects of dietary K and Na additions on metabolism of lambs. Lambs were randomly allotted to four treatments and fed 900 g/d of the following: control diet consisting of 50% ground tall fescue hay and 50% concentrate; K diet calculated to contain 4% K with K added as KCl; Na diet calculated to contain 4% Na with Na added as NaCl, and K-Na diet containing 2% K and 2% Na with K and Na added from the same sources as in the K and Na diets. Water intake and urine excretion were highest for lambs fed the Na diet. Dry matter (DM) and crude protein (CP) digestibilities were similar among treatments. The K-Na diet resulted in decreased (P less than .05) acid detergent fiber (ADF) digestibility compared with lambs fed the Na diet. Nitrogen (N) retention was highest (P less than .05) in lambs fed the K diet and lowest in those fed the Na diet. Rumen NH3-N was lower (P less than .05) in lambs fed the Na diet compared with controls. Rumen K at 2 and 6 h postfeeding was highest (P less than .05) and rumen Na at 6 h lowest (P less than .05) for lambs fed the K diet. Plasma K values at both sampling times were highest (P less than .05) in lambs fed the K diet. At 6 h postfeeding, plasma Mg was higher in control lambs compared with those fed the K-Na diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth, nutrient utilization and intestinal morphology of pigs fed high-fiber diets

Two trials (24 and 48 pigs; 9.7 kg initial body weight) were conducted to determine the effects of dietary fiber on growth, nutrient utilization and intestinal morphology of young pigs. The four diets fed were: basal corn-soybean meal (B), 15% oat hulls (OH), 15% soybean hulls (SH), and 20% alfalfa meal (AM). Fiber source did not have major effects on performance in a 35-d feeding trial. Balance trials (7-d duration) were conducted 32 d (Trial 1) or 6 d (Trial 2) after completion of the feeding trials. Feed intakes were equalized at 8.7% (Trial 1) or 10.3% (Trial 2) of initial body weight (kg.75). All fiber sources decreased apparent digestibilities of N, energy and dry matter (P less than .05) with no effect on N retention. Apparent digestibilities of neutral and acid detergent fiber, cellulose, and hemicellulose were reduced by OH and AM (P less than .01), but not by SH. Fiber sources did not affect apparent Ca, P, Zn or Mn absorption or retention, or Mg absorption, but decrease Mg retention (P less than .05). Apparent Na absorption was decreased by OH and increased by AM (P less than .05) but was unaffected by SH. All fiber sources increased K intake, but only SH and AM increased apparent K absorption (P less than .05). Fiber sources did not affect Na or K retention. The OH increased Cu intake and balance (P less than .05). All fiber sources increased Fe intake, but only SH and AM increased (P less than .05) Fe balance. Villus shape and surface morphology in jejunum and ileum examined by scanning electron microscopy (Trial 1 only) appeared to be independent of diet. However, jejunum villus morphologies of two pigs fed AM were characterized by loss of epithelial cells and microvilli at the villus apex, and ileum villi were blunted and frequently folded in one pig fed SH. Fiber sources at the levels included in a corn-soybean meal diet fed in this study had only a minimal impact on performance and utilization of minerals and N and intestinal structure, although apparent energy utilization was decreased.     

Net nutrient flux in visceral tissues of lambs fed diets differing in supplemental nitrogen source.

Eight multicatheterized wethers (35.9 +/- .8 kg BW) were used in a replicated 4 x 4 Latin square design to measure N retention and net uptake and release of plasma metabolites across the portal-drained viscera (PDV), hepatic (HEP), and total splanchnic (TS) tissues in response to changes in supplemental N source. Treatments selected to provide different amounts of undegradable intake protein (UIP) were urea, soybean meal (SBM), poultry by-product meal (PBM), and bloodmeal:corn gluten meal (BMCGM; 50:50 CP basis). Diets (urea, SBM, PBM, and BMCGM) contained 12.9, 13.8, 13.6, and 13.2% CP, respectively. Periods were 10 d, with total feces and urine collected on d 7 to 10 and blood sampled on d 10. Wethers were fed at 2% of BW in 12 daily portions. Nitrogen retention was 2.2, 3.3, 4.1, and 4.4 g/d for urea, SBM, PBM, and BMCGM, respectively. Urea had less (P < .01) N retention than SBM, PBM, and BMCGM; SBM had less N retention (P < .01) than PBM and BMCGM. Arterial, portal, and hepatic plasma flows were greater (P < .09) for SBM than for PBM and BMCGM (21 vs 16, 17; 84 vs 72, 72; 105 vs 87, 88 L/h). Portal plasma flow was greater (P < .10) for urea than for SBM, PBM, and BMCGM (85 vs 84, 72, 72 L/h). Portal-drained viscera and TS alpha-amino N (AAN) fluxes were less (P < .05) for PBM than for BMCGM (20.5 vs 26.6 and 7.2 vs 15.1 mmol/h), but TS AAN flux was less (P < .05) for urea than for SBM, PBM, and BMCGM (6.9 vs 16.9, 7.2, 15.1 mmol/h). Portal-drained viscera flux and HEP removal of NH3 N were greater (P < .001) for SBM than for PBM and BMCGM (27.7 vs 19.4, 20.6; -28.1 vs -20.0, -21.4 mmol/h). Gut use was less (P = .07) and HEP and TS fluxes of urea N were greater (P < .01) for SBM than for PBM and BMCGM (-4.92 vs -8.32, -7.93; 25.87 vs 16.54, 20.00; 20.95 vs 8.22, 12.07 mmol/h). These data suggest that PBM and BMCGM improved efficiency of N use compared with urea and SBM by reducing urinary N loss.     

ORIGINAL ARTICLE: Nitrogen and energy utilization in lactating dairy goats fed diets with different legume seeds

The N and energy utilization of diets with different legume seeds was analysed in lactating goats. Four isonitrogenous and isoenergetic diets were used and in each case 30% of the protein was supplied by one of four different legume seeds: lupins (L), faba beans (FB), bitter vetch (BV) and vetch (V). A group of eight Granadina goats, allocated to a replicated 4 × 4 Latin Square, were used. The N and energy utilization of the different diets may be considered adequate; milk N/intake N was approximately 0.20, milk N/N balance was approximately 0.50 and milk energy/metabolizable energy was approximately 0.30. Under similar N and energy intakes, faecal and urinary excretion of N and the quantities in milk did not vary significantly. However, the partition of the N balance between milk production and deposit within the body varied depending on the diet. Although this N available to the metabolism was the highest for the FB diet, the quantity of this directed to milk was the lowest. Finally, the faecal and urinary excretion with respect to the quantity directed to milk production did not vary significantly among the different diets.     

Phyzyme XP phytase improves growth performance and nutrient utilization in wheat-based diets fed to weaned pigs

The effect of phytase (Phyzyme XP) on performance and nutrient utilization in piglets fed wheat-based diets was evaluated using 24 male pigs averaging 7 kg. Four experimental diets containing either 0 (positive control, adequate nutrients), 0 (negative control (NC), reduced nutrients), 500 or 1000 U/kg of phytase were used for each of two dietary phases (day 0 to 14 and day 14 to 33). Feed and water were provided ad libitum. Animals were weighed at weekly intervals until day 28 and feed intake (DFI) recorded daily. From day 28 to 33 pigs were fed at 3 times maintenance energy intake and DFI recorded. Total amounts of faeces and urine were recorded for each individually housed pig. Digestibilities and balance of dry matter (DM), phosphorus (P), calcium (Ca), nitrogen (N) and gross energy (GE) were calculated for feed, faeces and urine. Compared to the NC, daily live weight gain was improved (P < 0.05) for pigs receiving the highest level of supplemental phytase in phase 2. Phytase addition at 1000 FTU/kg also increased faecal digestibilities of P and Ca (P < 0.05). Contrasts comparing NC and Phytase diets showed that Ca (P < 0.02) and P (P < 0.05) balance were improved.     

Rumen fermentation and nitrogen balance of lambs fed diets containing plant extracts rich in tannins and saponins, and associated emissions of nitrogen and methane.

Tannins were added to experimental diets at levels of 1 and 2 g/kg DM (hydrolysable tannins; Castanea sativa wood extract) and saponins at 2 and 30 mg/kg DM (sarsaponin; Yucca schidigera extract). These levels were far below thresholds expected to be adverse in ruminants. Effects were measured in lambs by comparison with unsupplemented control diets calculated to be either deficient (10%) or adequate in protein. The diets consisted of hay, concentrate (1:1) and extra wheat starch with increasing body weight. Ruminal pH, VFA concentration, protozoa count and apparent digestibilities of organic matter and fibre did not differ among treatments. The low tannin dose significantly decreased bacteria count compared to the high saponin dose. Saponin supplementation and the high tannin dose showed some potential to reduce ruminal ammonia concentration. This was associated with weak trends towards lower urine N excretion (only tannins) and ammonia emission from manure. Methane release was increased by the low tannin dose compared to the unsupplemented control. Diet effects on heat production were not systematic. In conclusion, the extracts rich in tannins or saponins gave only slight indications for either increased body nitrogen retention or reduced nitrogen emission. However, effects might have been larger with more pronounced dietary protein deficit.     

Impact of heating-degree-day accumulation during bermudagrass hay storage on nutrient utilization by lambs.

Spontaneous heating in stored alfalfa (Medicago sativa) has reduced forage quality and DM and N digestibility through microbial respiration and Maillard polymer formation. The impact of heating-degree-day (HDD) accumulation in stored bermudagrass (Cynodon dactylon [L.] Pers.) was evaluated for its effect on nutrient utilization by lambs. Twenty Rambouillet wether lambs (53.1 +/- 0.74 kg) were used in a completely randomized total collection experiment. The hays selected for this study had previously undergone spontaneous heating, producing either 5, 119, 201, 273, or 401 HDD (> 35 degrees C) during a 60-d storage period. Lambs were offered diets of these hays at 1.5% of BW. Dry matter intake did not differ (P = 0.59) among hays. Linear relationships were detected between HDD and apparent digestibilities of DM (y = 59.1 - 0.016x; P < 0.01; R2 = 0.37), OM (y = 59.3 - 0.017x; P < 0.01; R2 = 0.43), NDF (y = 66.4 - 0.012x; P = 0.01; R2 = 0.30), and hemicellulose (y = 74.0 - 0.012x; P = 0.02; R2 = 0.27). Similarly, significant regressions were observed for fecal N excretion (g/d; y = 4.70 + 0.004x; P < 0.01; R2 = 0.68), apparent N absorbed (g/d; y = 7.4 - 0.005x; P < 0.01; R2 = 0.50), apparent N absorption (%; y = 61.2 - 0.038x; P < 0.01; R2 = 0.71), apparent neutral detergent insoluble nitrogen digestibility (%; y = 85.8 - 0.026x; P = 0.01; R2 = 0.73), and apparent acid detergent insoluble nitrogen digestibility (%; y = 1.5 + 0.101x; P < 0.01; R2 = 0.62). Therefore, spontaneous heating during the storage of bermudagrass hay has a negative effect on dry matter and fiber digestion and nitrogen absorption by lambs.     

Effect of protein supplementation on expression and distribution of urea transporter-B in lambs fed low-quality forage

Two experiments were conducted to determine the effects of ruminal protein degradability, supplementation frequency, and increasing dietary protein on the expression and distribution of urea transporter-B (UT-B) in lambs fed low-quality forage (mature crested wheatgrass hay; 4.2 to 4.7% CP). In Exp. 1, 15 Dorset wether lambs (initial BW=45.8+/-1.3 kg) were blocked by initial BW and assigned to 1 of 3 treatments within a randomized complete block design for 28 d, with supplements fed to achieve 7, 10, or 13% total dietary CP. In Exp. 2, 13 Dorset wether lambs (initial BW=34+/-4 kg) were used in a completely randomized design and given 1 of 4 isonitrogenous supplements: 1) ruminally degradable protein (RDP) fed daily (n=3), 2) RDP fed on alternate days (n=3), 3) ruminally undegradable protein (RUP) fed on alternate days (n=3), or 4) a 50:50 mixture of RDP and RUP fed on alternate days (n=4) for 18 d. Alternate-day treatments were fed at twice that of daily supplementation. On the last day of both experiments, lambs were killed and samples taken for Western blot analyses for UT-B. Immunoblotting using a rabbit polyclonal antibody to UT-B confirmed the presence of distinct 32-kDa (consistent with a nonglycosylated UT-B protein) and 47-kDa (probable N-glycosylated form of UT-B) protein bands in all 9 tissues analyzed. In both experiments, the liver, dorsal rumen, reticulum, and ventral rumen displayed strong bands at 32 kDa and lighter bands at 47 kDa, whereas the cecum, large colon, spiral colon, and parotid salivary gland displayed slight 32-kDa bands and stronger, more visible bands at 47 kDa. Both protein bands were apparent in the kidney at similar visual intensities in Exp. 1, whereas the relative intensities of the 2 UT-B bands in the kidney were variable, and appeared somewhat reciprocal among animals in Exp. 2. Although the abundance of the 47-kDa UT-B band in the ventral rumen was greater (P=0.03) in lambs fed RDP daily in Exp. 2, no other treatment differences (P >or= 0.15 to 0.99) in the abundance of the 32- or 47-kDa UT-B proteins within tissues were observed in either experiment. Although protein supplementation strategy had little effect on UT-B expression in tissues other than the ventral rumen, differences in the degree of glycosylation of UT-B across tissues may provide insight into its regulation.     

Apparent digestibility and nutrient balance in lambs fed different levels of flatpea hay.

Apparent digestibility and nutrient utilization were studied in a digestion and balance trial with 30 wether lambs (BW 32 kg). Lambs were blocked by weight and allotted randomly to five diets with ratios of alfalfa (Medicago sativa L.) to 'Lathco' flatpea (Lathyrus sylvestris L.) hay of 100:0, 75:25, 50:50, 25:75, and 0:100. Alfalfa was harvested in the early bloom stage and flatpea was harvested in the vegetative stage. Digestibilities of DM, NDF, ADF, cellulose, hemicellulose, and energy decreased linearly (P less than .05) as the level of flatpea hay increased to values of 53.3, 32.4, 39.9, 46.0, 40.5, and 52.5%, respectively, for 100% flatpea hay. Nitrogen retention (9 to 15% of intake) was not affected by level of flatpea hay. Ruminal pH, NH3 N, and blood urea N increased linearly (P less than .001) as level of flatpea increased in the diet, apparently a reflection of dietary N level. Calcium excretion decreased linearly (P less than .01) with increased proportions of flatpea hay and was related to dietary intake of Ca. Apparent absorption and retention showed a cubic effect (P less than .05). No clinical signs of toxicity were observed in any of the lambs during the 20-d metabolism trial. Vegetative flatpea is potentially valuable as a forage for feeding ruminants.     

Condensed tannins from Sesbania sesban and Desmodium intortum as a means of Haemonchus contortus control in goats

Two experiments were conducted to determine whether the proanthocyanidin (condensed tannin)-containing forage legumes Desmodium intortum cv Greenleaf and Sesbania sesban (accession 15019) could be integrated into a feeding management strategy as a means of Haemonchus contortus control in goats. The anthelmintic effects of condensed tannin extracts from the two legumes on H. contortus L₃ larvae were studied in an in vitro larval migration inhibition system. The extracts inhibited larval migration in a dose-dependent manner, and at concentrations from 1,000???g/ml condensed tannin, the extract from D. intortum caused a significantly higher inhibition of larval migration than did the corresponding concentrations of the S. sesban extract (P?<?0.01). Prolonged feeding of tanniniferous forage legumes showed that animals receiving D. intortum had the lowest total worm burden, the lowest female to male parasite ratio, the lowest number of eggs in the uterus of each female worm and the lowest per capita fecundity (P?<?0.01). However, there was no change in the performance (weight gain) of parasite-infected goats probably due to incomplete removal of the parasite or prolonged confinement of goats in small pens, which calls for further investigation. However, since there is no single efficient method in control of parasites, based on the obtained data from this experiment, integrated feeding of D. intortum with other suitable method of parasite control is thus suggested.     

Enhancement of phosphorus utilization in growing pigs fed phytate-rich diets by using rye bran.

Some cereal by-products, such as bran, exhibit a high phytase activity that may enhance phytate P digestibility. This was studied in growing pigs fed a phytase-rich (1,200 IU/kg) diet containing 20% rye bran. The trial involved 12 animals; six were fed a control diet and six were fed a diet containing rye bran for 2 mo. Both diets contained the same levels of energy, protein, Ca (.7%) and total P (.4%). No inorganic P was added; thus, the dietary P was mainly phytic. Pigs fed the control diet, in contrast to those fed the diet containing rye bran, developed a P deficiency, as indicated by hypophosphatemia, hypophosphaturia, hyperhydroxyprolinuria, hypercalcemia, and hypercalciuria. Phosphorus from the rye bran diet was more completely absorbed (55 vs 36%) and retained (50 vs 36%) than that from the control diet. Calcium absorption was equal for the two diets, but Ca retention was higher in pigs fed rye bran than in controls. Pigs fed the rye bran diet showed greater bone density, ash content, and bending moments than controls. In conclusion, high dietary phytase levels or phytase-rich by-products increased phytate P availability and consequently improved bone scores.     

Energy utilization and blood traits of ponies fed fat-supplemented diets

The digestibility and heat production values for three fats of different origin were determined. Four pony geldings (225 kg) were used in a study consisting of four successive digestion trials utilizing a 4 X 4 Latin square design. The four dietary treatments were basal alone and supplemented with 15% corn oil, blended fat or inedible tallow. The blended fat was composed of a mixture of animal and vegetable fats. A 7-d preliminary period preceded a 7-d total fecal collection period for each trial. Heat production values were obtained by indirect calorimetry and calculated from oxygen consumption data. Fat supplementation increased (P less than .05) dietary metabolizable energy from a basal value of 3,224 kcal.kg intake-1.d-1 to a mean value of 3,984 kcal.kg intake-1.d-1 for the three fat diets. No difference in heat production was observed among the diets, averaging 2,883 kcal.kg intake-1.d-1. Fats increased (P less than .05) the energy balance (metabolizable energy-heat production) approximately 88% over the basal. Corn oil and blended fat produced the greatest energy balance of the fats. Utilization of energy in fats, calculated by difference, was not different, but tended to be highest in blended fat and lowest in the corn oil. Apparent fatty acid digestibility increased (P less than .05) with the addition of fat to the basal, partially due to the dilution of endogenous fecal fat, but digestion coefficients were not different (P greater than .40) among the high fat diets.     

Site and extent of nutrient digestion by steers fed a low-quality bromegrass hay diet with incremental levels of soybean hull substitution.

Five ruminally and duodenally cannulated steers were fed bromegrass hay (H; 5.6% CP; 70.9% cell wall) substituted with 0, 15, 30, 45, or 60% soybean hulls (SH; 10.5% CP; 87.9% cell wall) at 90% of ad libitum DMI. Diets were made isonitrogenous (11% CP) by addition of isolated soybean protein (91.5% CP). Total ruminal VFA concentration, molar proportion of acetate, and molar acetate:propionate ratio increased (linear; P less than .02) with increasing level of SH substitution, but propionate (mol/100 mol) and ruminal fluid passage rate decreased (linear; P less than .01). Ruminal pH and ammonia concentration decreased more rapidly, and to a greater extent and duration, as level of SH increased; neither was decreased to levels considered detrimental to fiber digestion. Ruminal and total tract DM, OM, and cell wall digestibilities increased (linear; P less than .01), whereas total tract N digestibility decreased (linear; P = .03), as level of SH increased Total N flow to the duodenum increased (linear, P = .03) with increasing level of SH, and microbial N flow tended (cubic, P = .09) to increase. Microbial efficiencies were unchanged (P = .10) with SH level. True ruminal digestibilities of N did not differ (P greater than .10) among diets. Rate of in situ DM disappearance of H and SH was not influenced (P greater than .10) by SH substitution, although rate tended to be fastest with 30 and 45% SH (quadratic, P = .14). We infer from these data that SH can replace 60% of the DMI of a low-quality forage diet without decreasing OM or cell wall digestion.     

Estimated nutrient content of diets commonly fed to pet birds

The owners of 135 pet birds were surveyed by questionnaire to determine their birds' weekly food consumption. The birds were divided into six food groups on the basis of the amounts of seeds, formulated products and human food they consumed. The formulated products and seeds were analysed for their nutrient content by two independent laboratories, the nutrient content of the human foods was obtained from a standard nutrition reference, and each bird's nutrient intake was estimated. The dietary content of individual nutrients was then compared with the estimated maintenance requirements for pet birds. Birds consuming less than approximately 50 per cent of their diets as formulated products had inadequate intakes of vitamins A and D3, and calcium. Diets high in human food were low in protein, energy, vitamins and minerals. Diets high in seed were excessive in fat and deficient in vitamins A and D3, and calcium.     

Alteration of nitrogen metabolism by alpha-ketoglutarate administration in growing lambs fed high nonprotein nitrogen-containing diets

Two completely randomized design experiments were conducted, using either 10, 38-kg (Exp. 1) or 10, 26-kg (Exp. 2) Hampshire x Western wether lambs, to study the effects of alpha-ketoglutarate (AKG) administration on N metabolism. Lambs were fed 890 and 885 g DM/d in Exp. 1 and 2, respectively, of corn-cottonseed hull basal diets with urea added to attain CP levels of 10.6 and 10.5% in Exp. 1 and 2, respectively. Experiments consisted of 10 d of adaptation followed by 7 d of infusion and excreta collection. Lambs were infused continuously either i.v. (Exp. 1) or abomasally (Exp. 2) with control solutions (CON) or solutions containing 41.3 g AKG/d (AKG). In Exp. 1, fecal and urinary N excretion and N retention were not affected (P greater than .10) by treatment. Compared to CON in Exp. 2, AKG infusion increased (P less than .10) fecal N output (6.6 vs 5.9 g N/d) but did not affect (P greater than .10) the amount of N retained (4.4 vs 3.5 g N/d). Compared to CON, AKG increased (P less than .10) urinary NH3 N excretion in Exp. 1. Serum urea N was lower (P greater than .10) for AKG than for CON in Exp. 1 but was not affected (P greater than .10) by treatment in Exp. 2. In Exp. 1, AKG appeared to reduce activities of several serum enzymes that function in amino N metabolism. In Exp. 1, compared to CON, AKG decreased (P less than .10) aspartate but increased (P less than .10) asparagine in serum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Feeding behavior of feedlot lambs fed diets containing levels of cassava wastewater

In this study, we evaluated the effects of including cassava wastewater in the diet on the feeding behavior of feedlot lambs in 35 male uncastrated Santa Inês × Dorper crossbred lambs at an approximate age of 3 months, with an average live weight of 20.0?±?3.4 kg. Diets were formulated with hay of cassava shoots (roughage) and a concentrate based on corn and soybean, with a roughage:concentrate ratio of 50:50, plus inclusion of cassava wastewater at the levels of 0, 12, 24, 36, or 48 g/kg of the total diet. Feeding behavior was evaluated between the 46th and 52nd days of the experiment. Increasing cassava wastewater levels in the diet reduced (P?<?0.05) the intakes (kg/day) of dry matter and neutral detergent fiber as well as the efficiency of rumination (g/cud and g/h) of dry matter and neutral detergent fiber. The other behavioral parameters were not affected by wastewater inclusion in the diet. Therefore, the inclusion of up to 48 g/kg of cassava wastewater on fresh matter of diets is not recommended for feedlot lambs.