Effect of heat processing and storage on protein quality and lysine bioavailability of a commercial enteral product.

Several rat bioassays were conducted to evaluate protein quality and lysine (LYS) bioavailability (BIO) of Osmolite HN, a commercial enteral product, as affected by the severity of heat processing during sterilization and by storage of the products for 1 year. Without amino acid supplementation, the protein quality of Osmolite HN, as determined by protein efficiency ratio (PER), was lower than that of casein, regardless of heat treatment. With addition of the limiting amino acid, cystine, the PER of Osmolite HN was equivalent to that of cystine-fortified casein. Storage of the product for 1 year had no effect (p greater than 0.05) on PER, even though the products had darkened in color. Slope-ratio regression analysis (weight gain regressed on supplemental LYS intake) yielded a LYS BIO estimate of 94.4% for the Osmolite HN control relative to crystalline LYS. Partitioning weight gain into that resulting from LYS consumed in the basal diet and that resulting from the LYS supplement per se provided more accurate estimates of LYS BIO. This method estimated LYS BIO at 100% for the Osmolite HN products, regardless of heat treatment. With storage, LYS BIO decreased 11-12% in all of the Osmolite HN products. The decreased LYS BIO is of minimal nutritional significance in that overall protein quality of the products was not affected by storage. This is likely due to the fact that there is a plethora of lysine in Osmolite HN such that LYS is not a protein-quality limiting factor.

Methionine requirement of the finishing pig.

Two pig experiments were conducted using a methionine (Met)-deficient feather meal-corn-soybean meal basal diet (13% CP; 3,400 kcal ME/kg diet, .126% Met, 456% cystine) supplemented with an amino acid mixture (lysine, tryptophan, histidine, threonine and phenylalanine) to determine the Met requirement of finishing pigs between 50 and 80 kg live weight. Using young chicks in a Met bioavailability growth assay and cecectomized adult cockerels in a Met digestibility assay, the Met-deficient basal diet was found to contain .115% bioavailable and .110% digestible Met. These results gave a bioavailability estimate (relative to DL-Met set at 100%) of 91.3 +/- 2.5% and a true digestibility estimate of 87.0 +/- 2.2% for Met in the basal pig diet. In Exp. 1, 21 crossbred pigs averaging 61 kg initially were individually fed diets containing .115, .165 or .215% bioavailable Met for 21 d. Average daily gain and gain:feed ratio increased quadratically (P less than .05) as level of Met increased. In Exp. 2, 30 crossbred pigs averaging 53 kg were individually fed diets containing .115, .135, .155, .175 or .195% bioavailable Met for 27 d. Daily gain and gain;feed ratio responded linearly (P less than .01) as Met level increased. Based on the results of Exp. 2, the bioavailable Met requirement of finishing pigs in the weight range 50 to 80 kg was estimated to be .182% of the diet. Assuming an 88% bioavailability of Met in commercial diets based on corn and soybean meal, the total Met level needed in practice would be .207%. If 55% of the finishing pig's sulfur amino acid need can be furnished by cystine, the total sulfur amino acid requirement would be .45% of the diet.

Multiple concurrent stressors in chicks. 2. Effects on hematologic, body composition, and pathologic traits.

Effects of multiple concurrent stressors on Hubbard x Hubbard chicks (Days 10 to 17 posthatch) were studied in a 2(6)-factorial experiment employing as treatments aerial ammonia (A, 0 or 125 ppm), beak trimming (B, sham handled or beak trimmed/cauterized), coccidiosis (X, gavage with 0 or 6 x 10(5) sporulated Eimeria acervulina oocysts), intermittent electric shock (E, 0 or between 2.9 and 8.7 mA), heat stress (H, 30.4 or 34.8 C), and continuous noise (N, 80 or 95 dB). Packed-cell volume (PCV) was decreased by X and increased by A and H. A quadratic relationship between PCV and number of simultaneous stressors (order) was detected. Heterophil percentage was increased and lymphocyte percentage decreased by A, E, H, and order. Monocyte percentage was increased by N, eosinophil percentage increased by X, and basophil percentage decreased by A, X, and H. Basophil percentage decreased linearly with increasing order. Whole carcass water percentage was increased by X, chloroform-methanol extract percentage (dry matter) (CME) decreased by X, and CP percentage (dry matter) increased by A. Neither water, CME, nor CP percentage changed in relation to order. Lesion severity did not change in any tissue as stressor order increased. With few exceptions, each stressor affected hematologic, body composition, and pathologic traits in a similar manner whether imposed singly or concurrently with up to five other stressors. The results suggest that in practical production situations, where ordinarily poultry experience more than one stressor at the same time, effects of multiple concurrent unrelated stressors on performance traits can be estimated to a first approximation by summing effects of respective stressors when acting alone.

Histidine requirement of the young pig.

A histidine (HIS)-deficient, feather meal-corn-dried whey basal diet (19% protein and 3,200 Kcal ME/kg), supplemented with lysine, methionine and tryptophan, was employed to determine the HIS requirement of the growing pig between 10 and 20 kg live weight. Using a chick bioavailability growth assay, the HIS-deficient basal diet was found to contain .19% bioavailable HIS. A preliminary pig study established that the HIS-deficient basal diet was capable of supporting good growth of pigs when supplemented with sufficient L-HIS.HCl.H2O. In the second pig experiment, crossbred pigs with an average initial weight of 10 kg were kept in individual metabolism crates and were fed to appetite in two feedings the HIS-deficient basal diet supplemented with 0, .06, .12 or .18% L-HIS. Rate and efficiency of weight gain increased linearly between 0 and .12% supplemental HIS, but the highest supplemental level of HIS did not improve performance further. Plasma HIS increased, whereas plasma urea-N remained unchanged, as the level of dietary HIS increased. The third pig experiment employed narrower increments of .06, .09 or .12% supplemental HIS, and a linear response in both gain and feed efficiency occurred. Viewing all experiments together, the bioavailable HIS requirement of the 10- to 20-kg pig was .31% of the diet. Assuming an 85% bioavailability of HIS in commercial diets based on corn and soybean meal, the total HIS level needed in practice would be .36%.

Bioavailability of lysine in L-lysine.HCl.

True digestibility of lysine (LYS) in crystalline L-LYS.HCl and casein determined in cecectomized adult roosters was not significantly different from 100%. Subsequent 9-d growth assays were conducted to determine the bioavailability of LYS in casein, in L-LYS.HCl, and in a mixture of crystalline amino acids simulating casein's amino acid profile. Based on slope-ratio methodology, LYS bioavailability relative to casein was estimated to be 101.4 and 99.9% in L-LYS.HCl and in the casein-simulated amino acid mixture, respectively. Procedures also were developed for assessment of LYS bioavailability in crystalline L-LYS.HCl by comparing growth responses to intraperitoneally injected (IP-LYS) and crop-intubated LYS (CI-LYS) in chicks fed LYS-deficient corn-sesame meal diets. Graded increments of pH-adjusted L-LYS.HCl were administered twice daily in .5-ml doses during the course of 8-d growth assays. Chicks receiving CI-LYS also received .5 ml of IP saline at each dosing, and those receiving IP-LYS also received CI saline at each dosing. Slope-ratio multiple linear regression of gain (g) regressed on LYS administered (mg) was assessed for both ad libitum-fed and meal-fed chicks. Linear growth responses to LYS were obtained with both routes of administration and in both feeding regimens. The CI-LYS slopes ranged from 103 to 125% of those obtained with IP-LYS administration. These results support the view that crystalline L-LYS.HCl is 100% digestible and bioavailable.

Characterization of the growth response obtained from Eimeria acervulina infection in chicks fed lysine-deficient diets.

Five assays were conducted with crossbred chicks to define the gain and feed efficiency response elicited when chicks fed lysine-deficient diets are infected with Eimeria acervulina. Crystalline amino acid diets that were either severely deficient in lysine (.12 or 20%) or adequate (.91%) were fed in the presence or absence of E. acervulina infection in the first four assays. In Assay 5, intact protein-based diets (corn-corn gluten meal) containing either .43 or 1.44% lysine were used to study the effects of lysine status on morbidity caused by E. acervulina infection. The infection was produced by crop intubating 1 X 10(6) sporulated E. acervulina oocysts either every other day in Assays 1, 2, and 5, or once at assay initiation in Assays 3 and 4. At deficient levels of dietary lysine, chicks by Day 6 after inoculations commenced exhibited marked gain and feed efficiency responses to E. acervulina inoculation. The same inoculation regimen in chicks fed diets adequate in lysine resulted in marked depressions in gain and feed efficiency. Monensin feeding diminished but did not entirely eliminate the inoculation response in lysine-deficient chicks. Throughout the assays, typical duodenal lesions were evident in infected chicks at necropsy, and dietary lysine status appeared to have no effect on the severity of lesions.

In vivo utilization of lysine and arginine in young chicks fed monensin.

Three chick growth assays were conducted to investigate the effects of monensin on lysine and arginine utilization in crossbred chicks (New Hampshire X Columbian). Chicks were fed either a low lysine corn-sesame meal diet containing graded increments of crystalline lysine.HCl (Assay 1) or an arginine-deficient casein-dextrose diet (Assay 2) supplemented with graded levels of L-arginine.HCl in the presence or absence of supplemental monensin (121 mg/kg). Based upon analysis by slope-ratio methodology (i.e., gain regressed on supplemental amino acid intake), the efficiency of L-lysine or L-arginine utilization was found to be the same in both monensin-fed and control chicks. In Assay 3, effects of monensin on the lysine-arginine antagonism were studied. Chicks were fed an arginine-deficient casein-dextrose diet supplemented with 1 or 2% L-lysine.acetate in the presence or absence of supplemental monensin. Growth performance was depressed by feeding both levels of supplemental L-lysine.acetate. Monensin had no effect on the magnitude of the growth depression caused by supplemental lysine. These results support the view that neither lysine nor arginine utilization is impaired by feeding monensin.

Interactive effects of monensin, roxarsone, and copper in young chickens infected with Eimeria tenella or a combination of E: tenella and E. acervulina.

Experiments were conducted with crossbred male chicks to evaluate the interactions among roxarsone (50 mg/kg), monensin (121 mg/kg), and copper sulfate (100 mg/kg) as treatments for experimental Eimeria tenella and E. acervulina infections. When diets containing monensin, roxarsone, or a combination of both were offered to chicks for 15 min or 1, 3, 5, or 8 days prior to E. tenella challenge (5 X 10(4) sporulated oocysts), monensin fed for 15 min or roxarsone fed for 1 day prior to challenge prevented morbidity. A mixed infection of E. tenella and E. acervulina (5 X 10(4) and 4 X 10(5) sporulated oocysts, respectively) reduced gain and gain:feed conversion ratios and caused severe duodenal and cecal lesions at Day 6 of the experiment. Infected chicks gained faster when diets were supplemented with either monensin or roxarsone, but monensin produced a larger response than roxarsone. The mixed infection decreased shank pigmentation, with amelioration activity evident from monensin but not from roxarsone. Lesion scores at Day 6 indicated markedly reduced lesions in the duodenum due to monensin but not due to roxarsone; likewise, reductions in cecal lesions occurred in birds fed roxarsone but less so in birds fed monensin. Lesion scores showed little evidence of additivity due to monensin and roxarsone. In general, copper sulfate exerted no independent or interactive effect on any of the parameters evaluated. In a subsequent experiment, the effect of feeding roxarsone in combination with the biological reducing agent, cysteine, was evaluated in E. tenella-infected chicks. Rate and efficiency of gain were improved and lesion scores were reduced by supplementary roxarsone.(ABSTRACT TRUNCATED AT 250 WORDS)

Lysine and sulfur amino acid utilization in Eimeria acervulina-infected chicks as affected by narasin.

The effects of supplemental narasin (80 mg/kg) on several dietary factors were investigated in chicks infected with Eimeria acervulina. In Trial 1, chicks were fed a lysine-deficient corn-corn gluten meal diet containing graded increments of crystalline L-lysine.HCl with or without narasin. Supplemental narasin increased weight gain and feed efficiency at all lysine levels fed. Based upon slope-ratio methodology, efficiency of L-lysine utilization was virtually the same in both narasin-fed and control chicks. Trials 2 and 3 evaluated the effect of narasin on methionine utilization in crossbred chicks fed a methionine-deficient soy-feather meal diet supplemented with graded levels of DL-methionine. Narasin supplementation increased weight gain, feed efficiency, and utilization of supplemental methionine in chicks infected with E. acervulina (Trial 2), but had no effect on any of the performance parameters in uninfected chicks (Trial 3). The effects of dietary protein level and source and dietary electrolyte balance on the narasin response of commercial broiler chicks infected with E. acervulina were studied in Trials 4 and 5, respectively. In Trial 4, narasin supplementation increased performance in all cases, and protein source or level had no effect on the narasin response. In Trial 5, rate and efficiency of gain were improved as the electrolyte balance (meq Na + K-Cl/kg diet) increased from 100 to 250, with no further improvement being observed from 250 to 350 meq. Supplemental narasin improved performance and no interaction between electrolyte balance and narasin was observed.

Feed additive studies with newly weaned pigs: efficacy of supplemental copper, antibiotics and organic acids.

Six experiments involving 706 newly weaned 28- to 32-d-old pigs were conducted to evaluate the efficacy of copper (Cu) sulfate (to provide 250 mg/kg Cu), antibiotic-sulfa combinations [chlortetracycline, 110 mg/kg + penicillin, 55 mg/kg + sulfamethazine, 110 mg/kg; i.e., Aureo-Sulfa-Penicillin (ASP) or tylosin, 110 mg/kg + sulfamethazine, 110 mg/kg; i.e., Tylosin-Sulfa (TS)] and anhydrous citric or fumaric acid (.75 to 1.5% of the diet). The basal experimental diet was a 19% crude protein (CP)-fortified corn-soybean meal diet (1.08% lysine) containing 7% dried whey and 3% fish meal. Marked and consistent gain and gain/feed responses occurred from the Cu supplement, particularly during the first week postweaning. The antibiotic-sulfa combinations were less efficacious than Cu during the 1-wk postweaning stress period. During either the 1- or 3-wk growth periods, ASP and TS showed additivity with Cu in promoting rate and efficiency of weight gain. Liver Cu was increased by Cu addition to the diet, but neither ASP nor TS affected Cu deposition in the liver. In a factorial experiment involving 17% (1.01% lysine) or 20% CP (1.23% lysine) corn-soybean meal diets containing either no dried whey or an addition of 25% whey, Cu supplementation elicited marked improvements in rate and efficiency of weight gain, particularly in diets without added whey. Likewise, whey addition improved pig performance, especially when added to the diets containing no supplemental Cu.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of 3-nitro-4-hydroxyphenylarsonic acid on copper utilization by the pig, rat and chick.

Experiments were conducted to examine the effect of dietary roxarsone (3-nitro-4-hydroxyphenylarsonic acid) on Cu utilization by the pig, chick and rat. A fortified corn-soybean meal diet was fed in each experiment. Roxarsone dramatically reduced liver Cu concentration at all levels of supplemental Cu fed. The level of roxarsone commonly fed, 50 mg/kg diet, resulted in a two- to fourfold depression in liver Cu concentration in all species studied. The effects of roxarsone on weight gain were more perplexing. In the chick, the diets containing 100 and 250 mg Cu/kg depressed growth in the presence, but not in the absence, of 50 mg/kg dietary roxarsone. In contrast, at toxic levels of Cu, roxarsone had no effect on (500 or 750 mg Cu/kg diet) or slightly alleviated (1,000 mg Cu/kg diet) the growth-depressing effects of Cu. In the rat, a roxarsone level of 50 mg/kg diet exacerbated the growth-depressing effect of 1,000 mg Cu/kg diet. However, Cu had no effect on the growth depression that resulted from feeding a toxic level of roxarsone (250 mg/kg diet). The antagonizing effects of roxarsone and Cu on weight gain were not evident in the pig. Supplemental Cu (250 mg/kg diet) improved weight gain, but not feed efficiency, in starter pigs. Roxarsone (50 mg/kg diet) had no effect on the growth-promoting effects of Cu.