Effect of dietary corn dried distillers grains with solubles, canola meal, and chloride on electrolyte balance, growth performance, and litter moisture of growing turkeys.

A study determined if dietary corn dried distillers grains with solubles (DDGS), canola meal (CM), or chloride (Cl) could adversely affect the performance and litter moisture of turkeys. A total of 1,089 Nicholas toms were used in a study during 2 to 14 wk of age. The poults were randomized into 99 pens (11 poults/pen) with number reduced to 10/pen at 8 wk. The factorial arrangement consisted of 3 diet sets [corn-soy (CS), CS + 20% DDGS, CS + 20% DDGS + 10% canola meal] and 3 Cl levels (0.22, 0.32, 0.42%), making 9 treatments distributed in 11 replicate blocks. Diets were formulated to be isocaloric with similar levels of digestible amino acids for each of 4 feeding phases. The dietary electrolyte balance varied with diet set and age period and ranged from 351 to 181 mEq/kg of diet (Na(+) + K(+) - Cl(-)) or 184 to -29 mEq/kg (Na(+) + K(+)) - (Cl(-) + S(2-)). Individual BW and pen feed residues were measured at each phase. Samples of litter were collected at 11 and 14 wk for measuring moisture. During 2 to 14 wk, no differences were observed in BW and ADG attributable to diet (P < 0.05). Birds fed diets containing DDGS or with CM consumed 6.0% more ADFI (P > 0.05). No differences were found for Cl or diet × Cl interaction for BW, ADG, or ADFI. The feed conversion ratio (FCR) was higher (P > 0.05) for birds fed diets containing DDGS or CM. A diet × Cl interaction was found for FCR during 8 to 14 wk; increasing Cl over 0.22% significantly increased the FCR by 3.0% only in diets containing DDGS with CM. Litter moisture was increased in diets containing DDGS or with CM, and by increased Cl. Including S in dietary electrolyte balance resulted in a better albeit weak correlation with ADG during 2 to 5 wk (-0.51 vs. -0.36) and FCR during 11 to 14 wk (-0.36 vs. -0.21). Due to the detrimental effect on FCR, high Cl should be avoided with DDGS and CM in turkey grower diets.

Effect of phytase supplementation to diets varying in chloride level on performance, litter moisture, foot pad score, and gait score of growing turkeys.

Phytase was examined as a means to improve turkey performance in diets with high Cl by modifying dietary electrolyte balance. Nicholas turkey toms (10 poults/pen; 10 replicates per pen) were fed corn-soy-distillers dried grains with solubles-canola meal-based diets (DDGS/CM) with varying Cl (0.2, 0.3, 0.4, or 0.5%) and phytase (0 or 500 phytase units/kg of diet), making 8 treatments (4 × 2 factorial). A ninth treatment was a corn-soy based diet (CS) with 0.3% Cl and without phytase (positive control). The diets were formulated to contain similar AMEn and digestible amino acid levels for each of 5 feeding periods (2 to 5, 5 to 8, 8 to 11, 11 to 14, and 14 to 17 wk of age) and fed in mash form. Turkey BW, ADG, ADFI, and feed conversion ratio (FCR) were determined for each pen along with litter moisture, foot pad, and gait scores. An ANOVA was conducted to determine the effects of Cl, phytase, and their interaction. Turkey BW, ADG, and ADFI decreased in a linear or curvilinear manner with increasing diet Cl (P < 05). At 17 wk of age, litter moisture and foot pad score showed a cubic trend with diet Cl (P < 0.05). Phytase improved FCR during 8 to 11 wk and increased litter moisture at 11 wk of age (P < 0.003). Phytase modified the FCR response to Cl during 2 to 5 and 14 to 17 wk of age at the 2 lowest levels of dietary Cl (P < 0.05). Turkeys fed CS had better BW and FCR through 17 wk of age compared with those receiving DDGS/CM at 0.3% Cl. Based on BW, minimum dietary electrolyte balance based on Na, K, and Cl was found to be 247, 217, 200, and 171 mEq/kg during 5 to 8, 8 to 11, 11 to 14, and 14 to 17 wk of age, respectively. The present findings emphasized the importance of considering Cl, phytase, and associated dietary electrolyte balance in turkey diets containing high levels of alternative byproducts.

Effect of supplementation of a dairy-originated probiotic bacterium, Propionibacterium freudenreichii subsp. freudenreichii, on the cecal microbiome of turkeys challenged with multidrug-resistant Salmonella Heidelberg.

A dairy-originated probiotic bacterium, Propionibacterium freudenreichii subsp. freudenreichii B3523 (PF) was found to be effective in reducing multidrug-resistant Salmonella Heidelberg (MDR SH) colonization in turkey poults (2-week-old) and growing (7-week-old) and finishing (12-week-old) turkeys. In this study, we explored the potential for microbiome modulation in the cecum of turkeys of different age groups due to PF supplementation in conjunction with MDR SH challenge. One-day-old commercial turkey poults were allocated to 3 treatment groups: negative control (N; turkeys without PF supplementation or SH challenge), SH control (S; turkeys challenged with SH without PF supplementation), and test group (P; turkeys supplemented with PF and challenged with SH). Turkeys were supplemented with 1010 CFU PF in 5-gallon (18.9 L) water until 7 or 12 week of age. At the 6th or 11th wk, turkeys were challenged with SH at 106 and 108 CFU/bird by crop gavage, respectively. After 2 and 7 d of challenge (2-d postinoculation [PI] and 7-d PI, respectively), cecal samples were collected and microbiome analysis was conducted using Illumina MiSeq. The experiments were repeated twice with 8 and 10 turkeys/group for 7- and 12-wk studies, respectively. Results indicated that the species richness and abundance (Shannon diversity index) was similar among the treatment groups. However, treatments caused apparent clustering of the samples among each other (P < 0.05). Firmicutes was the predominant phylum in the growing and finishing turkey cecum which was evenly distributed among the treatments except on wk 12 where the relative abundance of Firmicutes was significantly higher in P than in N (P = 0.02). The MDR SH challenge resulted in modulation of microflora such as Streptococcus, Gordonibacter, and Turicibacter (P < 0.05) in the S groups compared with the P and N groups, known to be associated with inflammatory responses in birds and mammals. The supplementation of PF increased the relative abundance of carbohydrate-fermenting and short-chain fatty acid-producing genera in the P group compared with the S group (P < 0.05). Moreover, the results revealed that PF supplementation potentially modulated the beneficial microbiota in the P group, which could mitigate SH carriage in turkeys.

Enhancing nutrient utilization of broiler chickens through supplemental enzymes.

The objective was to determine effects of adding phytase, amylase, and a cocktail of non-starch polysaccharide-degrading enzymes (NSPase) individually or in combinations to corn-soybean meal-based diet for broilers on apparent ileal digestibility (AID) of nutrients and dietary AMEn value. Four hundred and eighty male broiler chicks were divided into 80 groups and fed 8 diets in a completely randomized design (10 groups/diet) from day 15 to 21 of age. The diets were basal diet unsupplemented or supplemented with phytase (1,500 FTU/kg; Ronozyme HiPhos), amylase (80 KNU/kg, Ronozyme HiStarch), and NSPase (75 g/metric ton, Ronozyme Multigrain) individually or in all possible combinations. The basal diet contained the phytase at 1,000 FTU/kg, and was formulated to meet the NRC (1994) recommended nutrient requirements for broiler chickens except for ME, Ca, and non-phytate P, which were reduced by 150 kcal/kg, 0.18%, and 0.15%, respectively. Addition of phytase to the basal diet increased (P < 0.05) AID of P from 40.4 to 59.3%. Addition of amylase, NSPase or a combination of amylase and NSPase to the phytase-supplemented basal diet further increased (P < 0.05) AID of P to 63.4, 69.9, and 67.3%, respectively. Addition of phytase, amylase or a combination of amylase and NSPase to the basal diet did not affect dietary AMEn value. However, addition of NSPase alone or a combination of phytase and amylase or of phytase and NSPase to the basal diet improved (P < 0.05) dietary AMEn value from 3,203 to 3,339, 3,309 or 3,289 kcal/kg, respectively. In conclusion, it is more beneficial (with regard to AID of P and dietary AMEn) to add amylase and NSPase to phytase-supplemented diets for broilers. Because the basal diet contained phytase at 1,000 FTU/kg, the increase in AID of P due to supplemental phytase (1,500 FTU/kg) indicates that supplemental phytase at 2,500 FTU/kg is more beneficial with regard to improving AID of P than supplemental phytase at 1,000 FTU/kg.

Immunohistochemical detection of avian pneumovirus in formalin-fixed tissues.

An immunohistochemical staining technique (IHC) was developed to detect avian pneumovirus (APV) antigen in formalin-fixed, paraffin-embedded tissue sections using streptavidin-biotin immunoperoxidase staining. Samples of nasal turbinates and infraorbital sinuses were collected from 4-week-old poults experimentally inoculated with APV and from older turkeys infected during naturally occurring outbreaks of avian pneumovirus. Tissue was fixed in 10% buffered neutral formalin, embedded in paraffin, sectioned and stained. Inflammatory changes were observed microscopically in the mucosa and submucosa of the nasal turbinates and infraorbital sinuses of both experimentally inoculated poults and naturally infected birds. Viral antigen was detected by IHC in the ciliated epithelial cells of nasal turbinates and infraorbital sinuses.

The incidence of perirenal hemorrhage syndrome in six flocks of market turkey toms.

Four flocks of the Nicholas strain and two of the British United turkey (BUT) strain of large white market turkey toms were monitored from 8 to 19 weeks of age to identify the presence, incidence, age distribution, and possible cause(s) of perirenal hemorrhage syndrome (PHS), or acute hypertensive angiopathy. Mortality rates varied among the flocks from 0.81% to 1.78% of total poults started. Nicholas flocks has a distinct peak in mortality between 9 and 14 weeks of age. PHS was the main cause of mortality from 8 to 14 weeks of age in all flocks except one, and the incidence diminished after 15 weeks of age. No significant bacterial pathogens were detected in any of the PHS cases. Distinct peaks in overall weekly mortality between 10 and 13 weeks of age similar to those in the four Nicholas flocks were also observed in six of 10 Minnesota flocks surveyed separately.

The effects of stray voltage on turkey poults.

Three successive flocks of turkey poults experienced cumulative mortality of 10% to 26% through the fifth week of brooding. Stray electrical voltage was suspected after no definitive laboratory diagnosis could be made and no evidence of management deficiency was found. Alternating current voltages of 0.2 to 2.5 volts were detected between waterers and the floor and between the water line and gas line. When the water line was equipment-grounded to the electrical service entrance, the subsequent flock had no mortality problem. A series of experiments was conducted to determine the sensitivity of turkey poults to alternating current. Based on these experiments, the voltage levels measured at the farm probably did not cause the mortality experienced in the three flocks. The reason for the farm problem could have been 1) the poults experienced higher voltage than was present when measurements were taken, 2) the voltage may have been intermittent, or 3) there was a difference between the farm environment and the cage battery environment in the experiments.

Avian pneumovirus infection in Minnesota turkeys: experimental reproduction of the disease.

Avian pneumovirus (APV) is an emerging viral respiratory disease agent of turkeys in Minnesota. Clinical signs of APV infection include open mouth breathing, ocular and nasal discharge, and swelling of infraorbital sinuses. The virus spreads rapidly among flocks of susceptible turkeys and is associated with increased mortality rates. A flock of 11-wk-old turkeys experienced a respiratory problem characterized by coughing, sneezing, swollen sinuses, and nasal discharge. The reverse transcriptase-polymerase chain reaction (RT-PCR) performed on tissues from the nasal turbinates and tracheal tissues was positive for avian pneumovirus. Turbinate tissue was inoculated into chicken embryo fibroblasts, and cytopathic effect was observed after five blind passages. In an attempt to reproduce the disease, 50 microl of this cell culture-propagated virus was instilled into each conjunctival space and nostril of 23-day-old turkey poults. The poults were sacrificed at 2-day intervals for 12 days, and serum, tissues, and tracheal and cloacal swabs were collected. Between days 2 and 10 after exposure, the poults developed ocular and nasal discharge and swollen sinuses. The virus was detected by RT-PCR and virus isolation from the nasal turbinates of poults sacrificed on days 4 and 6 postinoculation. Antibodies to APV were detected by enzyme-linked immunosorbent assay.

Perirenal hemorrhage syndrome in market turkey toms: effect of management factors.

Differences in the overall mortality rates and mortality due to perirenal hemorrhage syndrome (PHS) were compared in large white Nicholas tom turkeys. The study evaluated the effects of 1) four different light and temperature treatments; 2) three feed additives proposed to have anti-stress effects (reserpine, acetylsalicylic acid, and increased calcium); 3) toe-clipping on mortality, various disease conditions, and production parameters. Mortality varied from 0.60% to 3.57% among groups. Increased room temperature (21 C), toe-clipping, step-up/step-down lighting, and dietary reserpine reduced the incidence of PHS as compared with lower room temperature (13 C), no toe-clipping, intermittent lighting (2 hours light, 4 hours dark), and no dietary reserpine. Dietary aspirin or elevated calcium levels had no effect on PHS incidence. Overall mortality was greatest in the warmer rooms.

Vaccination of turkeys with an avian pneumovirus isolate from the United States.

Four-week-old poults obtained from avian pneumovirus (APV) antibody-free parents were vaccinated with different serial 10-fold dilutions of cell culture-propagated APV vaccine. The birds were vaccinated with 50 microl into each conjunctival space and nostril (total of 200 microl). Each poult of each group was vaccinated in groups that received doses of 4 x 10(4), 4 x 10(3), 4 x 10(2), 4 x 10(1), or 4 x 10(0) 50% tissue culture infective dose (TCID50) of APV vaccine, respectively. Respiratory signs were seen between 3 and 12 days postvaccination (PV) in the poults that were vaccinated with 4 x 10(4), 4 x 10(3), and 4 x 10(2) TCID50, respectively. In these groups, APV was detected from swabs collected at 5 days PV and seroconversion was detected at 2 wk PV. The groups that were originally vaccinated with 4 x 10(1) and 4 x 10(0) TCID50 developed mild clinical signs after vaccination, but neither virus nor antibody was detected PV. At 2 wk PV (6 wk of age), birds from each group, along with five unvaccinated controls, were challenged with APV. Upon challenge, the 4 x 10(4) and 4 x 10(3) TCID50 groups were protected against development of clinical signs and were resistant to reinfection. The group previously vaccinated with 4 x 10(2) TCID50 developed clinical signs after challenge that were considerably milder than those seen in the groups that had previously been vaccinated with lower doses or no virus. Even though 4 x 10(2) TCID50 vaccine dose administered by intranasal ocular route resulted in infection, incomplete protection resulted with this pivotal dose. Upon challenge, the 4 x 10(1) and 4 x 10(0) TCID50 groups exhibited milder disease signs than those seen in the challenged unvaccinated controls. In these groups, APV was detected in preparations of swabs collected at 5 days postchallenge (PC) and seroconversion was detected at 2 wk PC. These results indicate that the dose of APV vaccine that causes protection is higher than that required to produce infection.

Neonatal avian pneumovirus infection in commercial turkeys.

Eleven market turkey flocks developed a respiratory disease characterized by coughing, swollen sinuses and nasal discharge. These symptoms first appeared between 3 and 16 days of age. Avian pneumovirus (APV) RNA was detected by reverse transcriptase (RT)-polymerase chain reaction (PCR) in six of six flocks tested. APV was detected by immunohistochemistry in turbinates of three of three affected flocks tested. Virus isolation attempts were negative. Ten of 11 flocks became seropositive on the APV enzyme-linked immunosorbent assay. Five weeks prior to hatch of these affected market turkeys, several breeder flocks in one geographic area had developed clinical signs and experienced decline in egg production typical of APV infection. In two breeder flocks, acute and convalescent sera indicated APV infection during the period of declining egg production. Attempts to detect APV RNA by RT-PCR from choanal cleft swabs of newly hatched poults were successful. Attempts to isolate the virus from these PCR-positive samples were negative.

Lysine requirements of growing turkeys in various temperature environments.

The lysine requirement of Large White male turkeys (Nicholas strain commercial cross) was determined in two experiments at different environmental temperatures for two age periods (8 to 12 and 16 to 20 wk of age). Response curves (segmented and exponential) were obtained by regressing body weight gain (grams/day) on dietary lysine concentration (percentage) or lysine intake (grams/day). Varying levels of dietary lysine were obtained by supplementing a corn-sesame meal diet with L-lysine.HCl. Temperature affected percentage lysine requirement as determined by the segmented (broken line) regression model during 8 to 12 wk of age in Experiment 1 (P less than .05) and in Experiment 2 (P less than .10). The requirements (mean +/- SE) by broken line regression for the 8 to 12-wk age period were: Experiment 1, 1.13 +/- .02 and 1.25 +/- .02% at 6 and 23 C, respectively, and Experiment 2, 1.10 +/- .03, and 1.23 +/- .04% at 7, 20, and 26 C, respectively. For the 16 to 20 wk age period the requirements for Experiment 1 were .75 +/- .02 and .77 +/- .03% at 8 and 24 C, respectively. For Experiment 2, requirements were .74 +/- .03, .72 +/- .02, and .78 +/- .02% at 7, 16, and 24 C, respectively. Percentage requirements by the exponential model showed the same patterns relative to temperature. Multiple regression analysis of gain on lysine intake and temperature indicated that variability in gain was primarily explained by intake (R2 ranged from .82 to .97) with deficient lysine intakes. Temperature environment also affected the gain response to lysine intake, resulting in different response curves at the different environmental temperatures.

Dietary biotin and turkey breeder performance.

The effect of biotin supplementation on turkey breeder hen performance was examined in two experiments. A corn-soybean meal-based breeder diet was supplemented with biotin to provide a low (.178 mg/kg) and high (.75 mg/kg) level of dietary biotin. The diets were fed to female-line hens (Nicholas strain) starting at time of light stimulation (31 and 30 wk of age for Experiments 1 and 2, respectively) for 27 wk. Each diet was fed to four replicate pens of 25 hens each. In Experiment 1, egg production and hatchability of fertile eggs from hens fed the high level of biotin was significantly greater (P < .05) during 50 to 54 wk of age. Egg production and hatchability were improved by 22 and 10%, respectively, from 50 to 54 wk of age. In Experiment 2, reproductive performance was unaffected by biotin level during 33 to 57 wk of age. The higher level of dietary biotin seemed beneficial in supporting later reproductive performance in one of two experiments.

Early protein undernutrition and subsequent realimentation in turkeys. 1. Effect of performance and body composition.

Male and female Large White Nicholas turkeys were fed corn and soybean meal diets for 24 and 20 wk, respectively. Control and low protein (75% of control in protein and 66% of control in lysine and methionine) diets were fed during 0 to 6 wk of age. Thereafter, both groups received the control diet. Body composition of turkeys was determined at 0, 2, 4, 6, 8, 12, 16, 20, and 24 (males), and at 0, 2, 4, 6, 8, 11, 14, 17, and 20 (females) wk of age. Compared with controls, undernourished turkeys had depressed body weight gain, lower feed intake, poorer feed efficiency, reduced carcass protein, increased carcass fat, and better efficiency of protein retention at 6 wk of age. During realimentation (after 6 wk of age), undernourished turkeys increased average daily feed consumption to that of controls and showed increased weight gains. By 24 and 20 wk of age, weights of undernourished male and female turkeys were no longer different from the weights of their respective controls. Feed efficiency of undernourished turkeys was better than that of controls during realimentation. Differences in body composition of undernourished and control turkeys were no longer evident after realimentation.

Early protein undernutrition and subsequent realimentation in turkeys. 2. Effect on weights and proportions of organs and tissues.

Male and female Large White Nicholas turkeys were fed corn and soybean meal diets for 24 and 20 wk, respectively. The same series was fed with a low protein modification (75% of control in protein and 66% of control in methionine and lysine per Mcal ME) during 0 to 6 wk of age. For the study of organ and tissue growth, six male turkeys per treatment were sampled at 2, 4, 6, 8, 12, 16, 20, and 24 wk of age. Six females per treatment were also sampled at 2, 4, 6, 8, 11, 14, 17, and 20 wk of age. Weights of eviscerated carcass, breast, thigh, drumstick, wing, back, neck, feathers, liver, heart, pancreas, alimentary tract less gizzard, and gizzard were depressed by early protein undernutrition to 6 wk of age. Compared with values for controls, undernutrition increased proportions of the liver, alimentary tract less gizzard, gizzard, and heart at 6 wk of age; proportions of the back, neck, feathers, and pancreas were not affected, but breast and thigh proportions were reduced. Compensatory growth during realimentation eliminated all differences between undernourished and control turkeys in weight and proportions of organs and tissues by 20 wk of age.

Protein, methionine, and lysine requirements of growing hen turkeys under various environmental temperatures.

Two experiments were conducted to study the protein and amino acid requirements of growing Large White female turkeys at temperatures of 7, 14, 21, and 28 C. In Experiment 1, five dietary treatment series (A, B, C, D and E) which ranged in protein content from 24.3 to 16.9, 20.4 to 14.2 and 17.8 to 11.9%, were fed during 8 to 11, 11 to 14, and 14 to 17 wk of age, respectively. The D diet series was also supplemented with methionine or lysine or both to equal the levels in the B series forming the D, DM, DL, and DML treatments. In Experiment 2, B and C protein levels were fed between 11 and 14 wk of age. Between 14 and 17 wk of age, the B, C, D, and E protein levels were fed to each group forming a 2 X 4 factorial arrangement. In Experiment 1, during 8 to 11 wk of age, body weight gain decreased when birds were fed diets containing less than 22.5% protein. From 11 to 14 wk of age, at 7 and 14 C, the C diet supported maximum gains but at 21 and 28 C, the B and A diets, respectively, resulted in heavier turkeys. With the D diet, methionine supplementation significantly (P less than .05) improved body weight of birds during 8 to 11 and 11 to 14 wk of age: lysine supplementation had no effect during 8 to 11 wk and inconsistent effects on gain during 11 to 14 and 14 to 17 wk of age. Results from 14 to 17 wk of age show that the protein requirement of female turkeys during this age was overestimated by the National Research Council in 1984.(ABSTRACT TRUNCATED AT 250 WORDS)

Nutritional evaluation of blood meal and feather meal for turkeys.

Three samples each of commercial blood meal (BL) and feather meal (FEA) were obtained in Minnesota. True amino acid availability (TAAA) and TMEn contents were determined using Large White male turkeys at 8 wk of age. Average TMEn were 3,458 and 2,976 kcal/kg (DM basis) for BL and FEA, respectively. The TAAA of BL ranged from 86 to 91% for each of 15 amino acids except for isoleucine (74%) and cystine (79%). The TAAA of FEA ranged from 59 to 83%. The three feather meals averaged 72, 72, and 76% in amino acid availability. Two ring-dried blood meals averaged 86 and 82% and one spray dried blood meal averaged 91% in amino acid availability. A positive linear relationship was found between TMEII and TAAA of blood and feather meal samples, suggesting the possibility of approximating the estimation of one from the other in certain ingredients of high protein content.

Content and relative bioavailability of phosphorus in distillers dried grains with solubles in chicks.

Total phosphorus analysis was performed on 20 samples of corn distillers dried grains with solubles (DDGS), and three experiments were conducted to determine the bioavailability of P in different samples of DDGS varying in Lys digestibility and heat processing (autoclaving). Relative bioavailability of P was estimated from tibia ash using the slope ratio method after chicks were fed a P-deficient corn-soybean meal diet supplemented with 0.05 or 0.10% P from KH2PO4 or supplemented with 2 levels of the test DDGS (7 to 25%). The mean total P value for the 20 DDGS samples was 0.73 +/- 0.04% (SD), with an average dry matter value of 88 +/- 0.8% (SD). In experiment 1, the bioavailability coefficient for P in a random sample of DDGS relative to KH2PO4 was 69%. In experiment 2, the relative bioavailabilities of P in low digestible Lys DDGS 1, low digestible Lys DDGS 2, and high digestible Lys DDGS 3 were 102, 82 and 75%, respectively (P < 0.05). For experiment 3, the P bioavailability coefficients for a light-colored nonautoclaved DDGS and the same DDGS autoclaved at 121 degrees C and 124 pKa were 75 and 87%, respectively (P < 0.05). Our results showed that the total P content of DDGS was similar to the 0.72% value reported by the NRC (1994), but the relative P bioavailability is higher than the value estimated from NRC (1994) based on table values for total and nonphytate P content. Our results also indicated that there is substantial variability in P bioavailability among different DDGS samples and suggest that increased heat processing may increase the bioavailability of P in DDGS.

Limiting amino acids after methionine and lysine with growing turkeys fed low-protein diets.

The effectiveness of Thr and other amino acids (AA) replacing CP in Met- and Lys-adequate diets of Large White male turkeys was studied from 6 wk to market age. Experiment (EXP) 1 examined efficacy of Thr and an AA grouping in corn-soybean (CS) diets containing 82.8 and 77.0% of NRC CP and in corn-soybean-canola-meat (CSCM) diets containing 85.2 and 79.4% of NRC (1984) CP. Experiment 2 compared AA responses in CSCM diets containing 100, 92.5, 85, and 77.5% of NRC (1994) CP. Compared with control CP, 1) 92.5% of NRC CP supported maximum BW, and supplemental Thr or Trp was without effect; 2) 82.8 to 85.2% of NRC CP resulted in reduced BW and breast meat yield (BMY), and supplemental Thr or Trp was ineffective in reversing this reduction, and 3) 77 to 79% of NRC CP resulted in depressed BW and BMY. Supplemental Thr provided a substantial positive BW but no BMY response, whereas a combination of Thr, Ile, Val, Arg, and Trp completely returned BW and partially returned BMY to that of the normal CP control. Turkeys on CS and CSCM assay diet series supported BW responses to CP and AA similarly. We concluded that in low-CP diets containing Met and Lys to requirement, supplemental Thr resulted in improved BW, whereas Thr, Ile, Val, Trp, and Arg returned BW, but not BMY, to normal CP control.

Identification of limiting amino acids in methionine- and lysine-supplemented low-protein diets for turkeys.

Large White male turkeys were fed 100, 85, 70, or 60% of NRC (1994) CP during 7 to 28 d (Experiment (EXP) 1), 8 to 12 wk (EXP 2), and 16 to 20 wk (EXP 3) of age. Diets contained corn, soybean, canola, and meat meals and were supplemented with Met and Lys to requirement. The influence of supplementary amino acids (AA) was studied at each protein level. Turkeys fed 85% CP gained BW similarly to those fed 100% of NRC CP (control) during each age range. Supplemental Thr, Val, and Ile during 7 to 28 d or 8 to 12 wk, or Thr during 16 to 20 wk, did not result in positive BW gain response. For turkeys fed 70% CP, BW gain was depressed compared with the normal-CP control in each period. During 7 to 28 d and 8 to 12 wk of age, the combination of Thr, Ile, Val, Arg, and Trp to 100% of NRC reversed the BW depression; here only Thr, Ile, and Val were essential components of the response. The BW depression during 16 to 20 wk was reversed by the combination of Thr, Ile, Val, and Trp. For turkeys fed 60% of CP, BW gain was severely depressed. The combination of Thr, Ile, Val, Trp, and Arg resulted in nearly complete BW recovery during each age.