Department of Poultry Science and the Interdepartmental Nutrition Program, North Carolina State University, Raleigh, NC 27695-7608

ABSTRACT
The ability of dietary zinc-methionine (Zn-Met) to enhance mononuclear-phagocytic function against Salmonella arizona and enteritidis was investigated in young turkeys. Feed/gain and body wt gain at 21 d of age were not affected by Zn-Met. The addition of 30 or 45 ppm Zn from Zn-Met to a Zn adequate diet significantly increased cutaneous basophil hypersensitivity to phytohemagglutinin-P. The clearance of intravenously administered S. enteritidis from blood was not affected by 30 ppm of supplemental Zn from Zn-Met. However, 30 ppm Zn from Zn-Met increased the reduction of intravenously administered S. arizona from spleen. Percentages of myeloid and mononuclear-phagocytic cells before and after S. enteritidis infection were not affected by supplemental Zn-Met. Turkeys supplemented with Zn-Met showed enhanced in vitro phagocytosis of S. enteritidis by Sephadex-elicited abdominal exudate cells. The phagocytosis of S. arizona was unaffected by Zn-Met.

Key words: zinc-methionine, macrophage, phagocytosis, salmonella, phytohemagglutinin-P, cellular immunity, turkey

Biological Trace Element Research, 1994. 42:217-229

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695

ABSTRACT
A major goal of many poultry producers is to attain good flock liveability. Historically, most poultry producers have manipulated environmental conditions and management to maximize bird health. In the past two decades there has been much research into nutritional regimes that improve bird health through immunomodulation. Commercial poultry environments contain ubiquitous micro-organisms that continuously challenge the immune system. Nutritional supplements that enhance immune system function may improve flock performance and be economically advantageous. This paper reviews the literature on zinc-methionine and the avian cellular immune system. Current knowledge of the effects of zinc on many animal models is reviewed and a hypothetical mechanism for the action of zinc-methionine on this system is discussed.

Key words: cellular immune system, disease resistance, helath, nutrition, poultry, zinc-methionine

World's Poultry Science Journal, 1996. 52:309-324

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
Betaine, a donor of labile methyl groups, can spare choline and methionine but cannot replace these compounds in poultry diets. Betaine is synthesized from choline by choline oxidase and it can donate methyl groups to homocysteine to form methionine. Physiologically, betaine is one of several compounds used by cells to regulate osmotic pressure. Among the potential benefits of its inclusion in poultry feeds are sparing choline, carcass fat reduction and aiding cell osmoregulation. Some feed ingredients are natural sources of betaine per se. This review considers the metabolism, functions and applications of betaine in poultry.

Key words: betaine, choline, methionine, osmoregulation, poultry

World's Poultry Science Journal, 1997. 53:125-139

North Carolina State University Department of Poultry Science, Scott Hall, Box 7608 Raleigh, NC 27695-7608

ABSTRACT
Macrophage cells isolated from the abdominal cavity of 21-day-old turkeys after a single injection of Sephadex suspension were used to quantitate the effects of direct in vitro exposure to deoxynivalenol (DON), 3-acetyldeoxynivalenol (3ac-DON), scirpentriol (STO), or 15-acetylscirpenol (15-MAS). Macrophage monolayers were established on glass surfaces and cells were exposed to graded levels of individual mycotoxins for 1 hour: DON, 20 - 640 ug/ul of culture; 3ac-DON, STO, 15-MAS, 20 - 1280 ug/ul of culture. All four mycotoxins caused dose-related effects. A concentration of 50 ug/ml DON caused a significant decrease in macrophage adherence, phagocytosis of opsonized SRBC, and number of opsonized SRBC per macrophage; at 200 ug/ml, phagocytosis of unopsonized SRBC was decreased. There were also increasing percentages of damaged macrophages with increasing DON doses as indicated by morphological alterations. Linear decreases in macrophage viability on exposure to 3-acDON and STO were observed. Moreover, STO and 15-MAS decreased macrophage adherence to glass and 3-acDON, STO, and 15-MAS induced macrophage morphological alterations. This study suggests that trichothecene mycotoxins may be immunosuppressive by affecting viability, adherence and phagocytic potential of mononuclear phagocytic cells of young turkeys.

Immunopharmacology and Immunotoxicology, 1995. 17(2):385-398

Department of Poultry Science and the Interdepartmental Nutrition Program, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
The influence of diets containing Zn-Met on in vitro and in vivo uptake of Escherichia coli by tbe mononuclear-phagocytic system was evaluated. Female Nicholas turkeys reared in battery brooders were supplemented with 40 ug Zn/g as Zn-Met in a corn soybean meal diet from 1 to 3 wk of age. Chemical analysis of the basal diets indicated that the basal diets contained 130 ug Zn/g and the Zn-Met diets contained 165 ug Zn/g. Each diet was fed to three replicate pens of 8 birds in Experiment 1 and three pens of 16 birds in Experiment 2. Body weight gain, feed conversion (FC), and clearance of injected E. coli from blood were determined in Experiments 1 and 2. Abdominal exudate cells (AEC) were recruited by intra-abdominal Sephadex injection. Substrate adherence potential and incidence of macrophages in AEC, phagocytosis of E. coli in vitro in terms of percentage phagocytic macrophages, and number of internalized E. coli per phagocytic macrophage, were quantified in Experiment 1. Plasma Zn concentrations and plasma alkaline phosphatase activity (ALKP) were determined in Experiment 2.
Supplemental Zn-Met improved 3-wk BW gain (P<.003) only in Experiment 2. Dietary Zn-Met increased mean adherence of cells by 69% (P<-.001). The number of phagocytized E. coli per macrophage did not differ significantly between treatments; however, E. coli clearance from blood was significantly improved in poults receiving Zn-Met in Experiment 2. Plasma Zn was higher in poults supplemented with Zn-Met prior to and after E. coli administration (P<.02). Plasma ALKP activity was marginally suppressed in plasma from poults supplemented with Zn-Met.

Key words: Escherichia coli, macrophage, zinc methionine, immunity, turkey

Poultry Science, 1994. 73:1381-1389

Department of Poultry Science, University of Arkcinsas, Fayetteville, Arkansas 72701

ABSTRACT
Experiments were conducted to examine effects of supplemental Zn on reproductive performance of young broiler breeders (BB) and evaluate the immunocompetence of their progeny. At 20 wk of age, 36 floor pens of 5 male and 30 female BB were fed either a 1) corn soybean meal (CSB) diet; 2) CSB supplemented with ZnO; 3) CSB supplemented with Zn-Met; 4) milo and corn-soybean meal (MCSB); 5) MCSB supplemented with ZnO; 6) MCSB supplemented with Zn-Met. These diets contained 72, 112, 112, 83, 123, and 123 mg Zn/kg of diet, respectively. All progeny received the same unmedicated CSB starter diet, and therefore treatments were derived from the potential carryover of the BB diets.
Supplemental Zn in either a CSB or MCSB diet resulted in no differences in egg weight, fertility, hatchability, chick weight, immune response variables, and foot pad scores of BB. The CSB diet increased (P<.05) BB antibody titers to SRBC when compared with MCSB grain sources. Supplemental Zn-Met in either a CSB or a MCSB diet fed to BB increased (P<.0001) cutaneous basal hypersensitivity to phytohemagglutinin-P in their progeny. Supplemental ZnO increased (P<.04) antibody titers to SRBC in the progeny of BB given a CSB or MCSB diet. However, progeny from BB given CSB diet had higher (P<.04) antibody titers to SRBC than progeny from BB given MCSB diet.

Key words: zinc, broiler breeder, progeny, reproductive performance, immunity

Poultry Science, 1993. 72:1492-1499

Department of Animal and Poultry Sciences, University of Arkansas, Fayetteville, Arkansas 72701

ABSTRACT
Three consecutive trials involving approximately 700 to 800 broilers (0 to 28 days) were conducted to examine effects on growth and immunity of chicks after supplementing dams with inorganic Zn versus organic Zn. Offspring from hens fed a basal diet (72 mg Zn/kg) or diets with 152 mg Zn/kg supplemented with ZnO or organic Zn-Met were randomized across four battery brooders. Chicks were fed a starter diet without supplemental Zn containing 100 mg Zn/kg or diets supplemented with 40 mg/kg Zn from ZnO and DL-Met or Zn-Met containing 140 mg Zn/kg. No differences among treatments (P>.05) were found in feed conversion or average BW. Supplemental Zn-Met in hen diet increased (P <.06) cellular immune response in progeny. Embryonic bone weights were higher (P<.05) in progeny when dams were fed Zn-Met. Zinc as Zn-Met in diets of dams and progeny enaanced primary antibody titers to Salmonella pullorum antigen.

Key words: zinc, methionine, progeny, immunity, bone

Poultry Science, 1992. 71:1201-1206

Nutri-Quest, Inc., Chesterfield, Missouri 63017

ABSTRACT
The effect of dietary Arg:Lys ratios and dietary electrolyte balance (DEB) on growth and carcass parameters of Large White toms was evaluated in one experiment from 8 to 20 wk of age. Growth, feed conversion, and carcass composition were measured. All toms received a common basal diet from 0 to 8 wk of age. At 8 wk of age, 600 toms were randomly placed into 40 pens (15 toms per pen). The corn-soybean meal-based experimental diets were fed from 8 to 12, 12 to 16, and 16 to 20 wk of age and evaluated two Arg:Lys ratios (0.98 vs 1.22) and two DEB levels (148 vs 202 mEq/kg of diet) in a complete factorial arrangement. All experimental diets were pelleted. Composite samples of protein-contributing ingredients and complete experimental diets were analyzed for all amino acids, CP, DM, Cl, Na, and K.
High and low average house temperature for the 8 to 20 wk period were 19 and 15 C, respectively. No interactions occurred between Arg:Lys ratios and DEB for any parameter measured except litter moisture. Increasing the Arg:Lys ratio improved 20-wk BW (P<0.027) and 8 to 20 wk gain (P<0.023). Feed:gain from 0 to 20 wk of age was decreased by increasing the Arg:Lys ratio (3.01 vs 2.94; P<0.026) and by increasing the DEB (3.01 vs 2.95; P<0.045). Dietary treatments did not affect mortality. Increasing DEB decreased cold carcass yield (P<0.020). Total breast meat yield was increased (P<-0.076) by 1% in toms fed the diets containing the 1.22 Arg:Lys ratio vs toms fed diets containing the 0.98 Arg:Lys ratio. Toms responded favorably to increasing the Arg:Lys ratio for growth, feed conversion, and breast meat yield independent of DEB level.

Key words: turkey, lysine, arginine, electrolyte balance, breast meat yield

Poultry Science, 1998. 77:864-869

Department of Poultry Science, North Carolina State University, Raleigh, North Carolina 27695-7608

ABSTRACT
Cytotoxic effects of T-2 tetraol, a T-2 toxin derivative, on the MQ-NCSU chicken macrophage cell line were quantified by direct in vitro exposure. Macrophage cultures were exposed to 1, 10, 20, 40, 80, 160, and 320 ug/mL of T-2 tetraol for 1 h. Macrophage viability and adherence to glass were measured microscopically after exposure to T-2 tetraol. Macrophage viability was reduced by increasing concentrations of T-2 tetraol (linear effect, P<0.001; quadratic effect, P<0.025). The ability of macrophages to adhere to glass surfaces was impaired by increasing concentrations of T-2 tetraol (linear effect, P<0.003). This experiment demonstrates that T-2 tetraol is cytotoxic to chicken macrophages in vitro.

Key words: Fusarium, mycotoxin, T-2 tetraol, chicken, macrophage

Poultry Science, 1997. 76:311-313

Nutri-Quest, Inc., Chesterfield, Missouri 63017

ABSTRACT
Two experiments were conducted to evaluate the effects of two dietary levels of lysine and four dietary levels of threonine in a factorial arrangement on broiler growth, carcass traits, and immunity. In both experiments, 120 broilers were allocated to each of 56 floor pens (6,720 total broilers). In Experiment 1, two levels of lysine (1.10 and 1.20% of diet) and four levels of threonine (0.68, 0.74, 0.80, and 0.86% of diet) were fed to broilers from 1 to 18 d of age in a sorghum-peanut meal diet. Body weight gain, feed:gain, mortality, and cellular and humoral immunity were measured. In Experiment 2, all broilers received a common basal diet up to 18 d of age. Experimental diets were fed from 18 to 34, 34 to 44, and 44 to 54 d of age. Two levels of lysine [100 and 105% of NRC (1994) recommendations] and four levels of threonine [83, 92, 100, and 108% of NRC (1994) recommendations] were included in the experimental diets for each age group (seven replications per treatment). The diets consisted of wheat (soft), corn gluten meal, soybean meal, and meat and bone meal. Weight gain, feed:gain, mortality, and carcass traits were measured at 54 d of age.
In Experiment 1, increasing dietary lysine from 1.10 to 1.20% from 1 to 18 d in broilers improved (P<0.001) BW gain (453 vs 488 g) and feed:gain (1.39 vs 1.33). No interactions between lysine and threonine were observed in Experiment 1. Differences in immune parameters or mortality were not observed. In Experiment 2, an interaction in 18 to 54 d weight gain occurred with the highest gain in broilers receiving dietary lysine and threonine levels equivalent to 100 and 83%, respectively, of NRC (1994) or lysine and threonine at levels of 105% and 100% of NRC (1994), respectively (P<0.05). Supplemental lysine (105% of the 1994 NRC) improved (P<0.01) 18 to 54 d feed:gain (2.30 vs 2.26). No differences in mortality occurred. Supplemental lysine increased preslaughter weight (P<0.05), but differences in carcass yield were not observed. Breast fillet yields were the highest (P<0.03) in broilers receiving 100% of NRC lysine and 83 or 92% of NRC threonine or 105% of NRC lysine and 100 or 108% of NRC threonine. In conclusion, additional lysine improved feed:gain independent of threonine from 1 to 54 d of age. However, lysine and threonine interact to increase weight gain and breast fillet yields.

Key words: lysine threonine, broiler, performance, breast meat yield

Poultry Science, 1997. 76:608-614

Nutri-Quest, Inc., Chesterfield, Missouri 63017 and Poultry Science Center, University of Arkansas, Fayetteville, Arkansas 72701

ABSTRACT
This experiment evaluates the effects of decreasing dietary CP, in addition to the effects of dietary supplements of L-Thr to low CP diets, in Large White Nicholas toms from 0 to 18 wk of age. Toms were fed dietary treatments consisting of four levels of dietary CP as a percentage of NRC (1994) recommendations (100, 92, 84, and 76% of NRC recommendations). Additional treatments consisted of supplements of L-Thr (0.1 and 0.2% of diet) added to the 92 and 84% NRC CP treatments. All eight dietary treatments were formulated to meet a minimum of 105% of NRC (1994) recommendations for Met, TSAA, Lys, Thr, and Trp. Body weight, feed conversion, mortality, and carcass composition responses were measured.
Decreasing CP to 84% of NRC resulted in 18-wk BW lower than that (P<0.001) of toms fed diets containing 100 or 92% of NRC CP; however, toms fed 84% of NRC CP diet supplemented with 0.1% L-Thr had 18-wk BW equal to (P<0.001) that of the 100 and 92% NRC CP treatments. Toms fed diets containing 76% of NRC CP had depressed BW and feed:gain in comparison to all other treatments. No adverse effects in cumulative feed:gain (0 to 18 wk) were noted by decreasing CP from 100 to 84% of the NRC recommendations. Mortality did not differ among treatments. Treatments had no effect on carcass fat expressed as a percentage of hot carcass weight. Breast meat yield (deboned Pectoralis major and Pectoralis minor) was highest (P<0.001) in toms fed the 100 and 92% NRC CP treatments. The 84 and 76% NRC CP treatments resulted in decreased breast meat yield regardless of L-Thr supplements. These results indicate that diets containing Met, TSAA, Lys, Thr, and Trp at a minimum of 105% NRC recommendations may support favorable breast meat yield when CP is decreased to 92% of the NRC (1994) recommendation. If growth and feed conversion are the desirable traits, rather than breast meat yield, CP levels below 92% of the NRC (1994) recommendation may support favorable responses.

Key words: turkey, dietary protein, growth, breast meat, threonine

Poultry Science, 1997. 76:1392-1397

Nutri-Quest, Inc., Chesterfield, Missouri 63017 and Department of Poultry Science and the Interdepartmental Nutrition Program, North Carolina State University, Raleigh, North Carolina 27695

ABSTRACT
A study was conducted to evaluate Thr responses m Large White (British United Turkeys) male turkeys during three time periods: 0 to 3, 3 to 6, and 6 to 9 wk of age. The Thr-deficient diets, fed in 3-wk intervals, were composed primarily of corn, peanut meal, poultry meal, and soybean meal as intact protein sources and supplemented with amino acids. Graded levels of L-Thr were added to the Thr-deficient diets. Another group of turkeys received a corn-soybean-poultry meal control diet in each time period. Diets were formulated to meet a minimum of 110% of suggested amino acid specifications (NRC, 1994) for all essential amino acids, except Thr. Feed intake, BW gain, and feed:gain responses were measured. Average environmental temperatures for Weeks 1, 2, and 3 were 29, 27, and 24 C, respectively. From 4 to 9 wk of age, average environmental temperatures varied between 24 and 35 C. Turkeys in each time period responded to Thr in a curvilinear manner with responses at the asymptote being equivalent to turkeys fed the corn-soybean meal control diets. Adequate dietary Thr levels for gain and feed:gain for the 0 to 3 wk period were 0.93% (3.21 g Thr/Mcal ME) and 0.97% (3.34 g Thr/Mcal ME) of diet, respectively. From 3 to 6 wk of age, the level of dietary Thr needed to support adequate BW gain and feed:gain was 0.88% of diet (2.81 g Thr/Mcal ME). The level of dietary Thr needed to support adequate BW gain and feed:gain from 6 to 9 wk of age was 0.77% of diet (2.30 g Thr/Mcal ME). These results indicate that the NRC (1994) estimations of Thr needs up to 9 wk of age are more than adequate.

Key words: turkey, threonine, amino acid, crude protein

Poultry Science, 1998. 77:1550-1555

Nutri-Quest Inc., Chesterfield, MO 63017; British United Turkeys of America, Lewisburg, WV 24901; O.K Industries, Inc., Fort Smith, AR 72902; Choctaw Maid Farms, Inc., Carthage, MS 39051; Wayne Farms, Gainesville, GA 30501

ABSTRACT
Marginal dietary deficiencies of threonine, the third limiting amino acid in broilers, may result in economic losses from increased feed conversion and reduced breast meat accretion. It is important, therefore, to meet the minimum dietary threonine level needed in a broiler diet. Few studies, however, have addressed the threonine needs of finishing broilers. Those which have do not agree with current NRC standards. This study was conducted to determine the level of threonine needed for performance, the carcass traits of finishing broilers, and the economic importance of threonine in terms of profitability.
A total of 4096 male commercial broilers received threonine-deficient diets containing corn, peanut meal, wheat middlings, poultry oil, and supplemental amino adds from 42 to 56 days of age. The experimental diets ranged from 0.45% to 0.8l% total dietary threonine in 0.06% increments. This study included a corn-soybean-poultry meal control diet. Growth, feed conversion, and carcass responses of hroilers fed tile experimental diets supplemented with surfeit threonine were equal to or better than responses obtained from broilers fed the control diet. A total dietary threonine level of 0.66% to 0.67% appears to be adequate to support good growth and carcass response in broilers from 42 to 56 days of age. Economic analysis indicated that the level of dietary threonine resulting in optimum profitability was near the level that resulted in optimum feed conversion and carcass composition.

Key words: amino acid, breast meat, broiler, economics, threonine

J. Appl. Poultry Res., 1999. 8:160-169

Nutri-Quest, Inc., Chesterfield, MO 63017; BioKyowa Inc., Chesterfield, MO 63017; Global Poulty Consulting Inc., Buford, GA 30519; Colorado Quality Research, Wellington, CO 80549

ABSTRACT
Providing adequate dietary lysine (Lys) to broilers is critical if the amount of saleable white meat is the economic objective. However, the period when Lys is most critical for breast development remains unclear. The objective of this study was to determine if dietary Lys in the starter and grower-finisher diets interact to affect live performance, mortality, and breast meat in commercial broilers. This study records two levels of Lys in the starter diets (95 and 115% of 1994 NRC) and three levels of Lys in the grower-finisher diets (85, 105, and 125% of 1994 NRC) fed to male broilers in diets composed of corn, soybean meal, corn gluten meal, poultry meal, and poultry oil.
Increasing Lys in the starter or grower-finisher diets increased both performance and mortality. Breast meat weight and yield increased when broilers received the highest Lys levels in the starter and grower-finisher diets. Feeding broilers inadequate dietary Lys in the starter period decreased finishing live performance and breast meat responses, irrespective of grower-finisher Lys levels. Dietary Lys levels above that considered adequate (125% of 1994 NRC) in the grower-finisher diets compensated for loss of breast meat due to Lys inadequacy in the starter diet, but compensatory breast meat accretion was not complete.

Key words: breast meat, broiler, lysine

J. Appl. Poultry Res., 1998. 7:351-358

Nutri-Quest, Inc., Chesterfield, MO 63017

ABSTRACT
Threonine is typically the third limiting amino acid in corn and soybean meal diets for broilers. However, reported threonine requirement values for broilers vary greatly, and the threonine requirement for growing broilers has been studied little. It is important to accurately meet threonine requirements for maintenance and tissue accretion as the bird ages.
Commercial broilers were fed threonine-deficient experimental diets composed of grain sorghum, peanut meal, corn, and poultry meal from 30 to 42 days of age. Performance of commercial broilers fed experimental diets containing surfeit threonine was equal to that of birds fed the corn and soybean meal control diet. Results indicate that the 21 to 42 day NRC threonine requirement of O.74% of diet is too high, based on the 30 to 42 day weight gain and feed gain response. However,the 30 to 42 day threonine requirement for breast traits may be higher than that of performance criteria. Future research should address threonine requirements in mature broilers for carcass traits.

Key words: breast meat yield, broiler, chicken, threonine

J. Appi. Poultry Res., 1997. 6:362-367

Nutri-Quest, Inc., Chesterfield, MO 63017

ABSTRACT
The cost of protein and energy have fluctuated dramatically for the feed industry during the last few years. As a consequence, feed formulation practices are directed toward economic analysis rather than optimal bird performance. In addition, use of alternate ingredients and amino acid formulation on a digestible basis has become more common in the United States.
The industrial production of methionine and lysine has resulted in poultry nutritionists reducing the level of dietary crude protein while maintaining bird performance and profitability. Indeed, the commercial availability of other amino acids may allow nutritionists to further decrease crude protein while more effectively meeting the birds' amino acid requirements for maintenance and tissue accretion. This review examines poultry literature on L-threonine and makes extrapolations relating to commercial situations. Functions of L-threonlne in metabolism and threonine's content in feedstuffs are discussed.

Key words: amino acid, broiler, low crude protein, threonine, turkey

J. Appl. Poultry Res., 1996. 5:358-367

Nutri-Quest Inc., Chesterfield, MO 63017 and Animal Sciences Center, University of Missouri, Columbia, MO 65211

ABSTRACT
For years poultry nutritionists have decreased the use of protein-rich feedstuffs by adding methionine and lysine. The extent to which crude protein can be decreased without compromising bird performance remains subject to much debate. Because threonine is the third limiting amino acid for broilers, two experiments were conducted to evaluate threonine's efficacy in low crude protein diets adequate in methionine and lysine. In Experiment 1, threonine supplementation to low crude protein diets improved some carcass measurements at 56 days of age although it failed to do so at 42 days of age. In Experiment 2, birds fed a low crude protein diet containing supplemental threonine had 21- to 42-day weight gain and feed conversion statistically equivalent to that of those fed a high crude protein diet. Low crude protein diets containing threonine-limiting ingredients may require supplemental L-threonine for optimal feed conversion and weight gain. Poultry nutritionists who formulate low crude protein broiler diets with threonine-limiting ingredients should pay careful attention to the level of dietary threonine to optimize feed conversion ratios and monetary returns.

Key words: amino acid, broiler, feed conversion, low crude protein, threonine

J. Appl. Poultry Res., 1996. 5:180-190

University of Arkansas, Fayetteville, AR 72701

ABSTRACT
A 22 week study was conducted with mature broiler breeders to evaluate their performance and immuno-response when fed a zinc-supplemented diet. Three dietary treatments were used: 1) a practical basal (conrol) diet containing 72 mg/kg of Zn and 0.357% methionine (Met); 2) the basal diet supplemented with 80 mg/kg of Zn from Zn Oxide and DL-Methionine to provide 152 mg/kg of Zn and 0.373% Met; and 3) the basal diet supplemented with 80 mg/kg Zn from Zn-Methionine to provide 152 mg/kg of Zn and 0.373% Met. Six replications of each dietary treatment were utilized, with each replication containing 40 females and 5 males. Daily feed allocation was 35 lb/100 birds. Egg production and livability were measured daily for the 22-wk trial. Fertility, hatchability, egg weights and chick weights were evaluated 4 times during the study. Cellular and humoral immunity were measured at week 22. Fertility and hatchability of eggs from birds fed the zinc-supplemented diets were not different from birds fed the control diet. Zinc-supplemented diets did not alter egg weight, chick weight, egg production, livability, and humoral or cellular immunity when compared to the control-fed birds. Significance levels were based on P<.05.

Key words: zinc, methionine, broiler breeder, performance, immune response

J. Appl. Poultry Res., 1992. 1:207-211

Department Poultry Science, North Carolina State University, Raleigh, NC 27695-7608; Department of Animal and Poultry Science, University of Guelph; Guelph, ON NIG 2W1, Canada; Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762; Department of Medicine, Medical University of South Carolina, Charleston, SC 29425

ABSTRACT
In recent years, there has been a growing perception that limitations in gastrointestinal absorption may be detrimental to post hatch survival and subsequent performance. This perception is based on a large body of information demonstrating that genetic selection for growth in domestic poultry alters intestinal structure from that of their wild counterparts. Furthermore, recent advances in our understanding of the energetic costs of absorption suggest that biochemical as well as structural changes in intestinal function have decreased absorptive function and efficiency in both chickens and turkeys. The recent discovery that some gastrointestinal peptides enhance nutrient absorption has allowed limited, direct testing of this hypothesis. The results of preliminary studies indicate that intestinal absorption enhancement technology may have beneficial practical application. More detailed studies are needed to fully assess the economic potential of intestinal absorption enhancement in poultry.

Key words: Gastrointestinal peptides, genetic selection, intestinal absorption

J. Appl. Poultry Res., 1999. 8:242-252.

Department of Poultry Science and Experimental Statistics Unit, Mississippi State University, Mississippi State, Mississippi 39762

ABSTRACT
Developmental relationships between yolk, embryo body, and embryo liver compositions during incubation were determined in two trials. In Trial 1, embryo body moisture, fat, and CP contents and embryo liver moisture and fat contents were determined. In Trial 2, relative yolk weights, moisture, fat, and fatty acid contents, relative wet and dry embryo weights and moisture contents, and relative wet and dry liver weights and moisture contents were determined. In Trial 1, embryo moisture decreased sigmoidally between Days 6 and 21, whereas embryo fat increased between Days 12 and 21 of incubation; embryo CP displayed sequential fluctuations throughout incubation. However, an overall significant decrease in embryo CP occurred between Days 6 and 21. Liver fat content increased between Days 12 and 21, whereas liver moisture decreased through Day 18, with a subsequent increase by Day 21. In Trial 2, relative yolk weight and moisture content decreased, whereas percentage yolk lipid content increased between Days 6 and 15. Relative wet and dry embryo weights changed in a similar manner, with rapid increases between Days 12 and 18 of incubation. Embryo moisture and CP were negatively correlated to embryo fat content. Furthermore, relative embryo and liver DM were related to yolk palmitic acid concentration, whereas yolk oleic acid was correlated only with liver DM. In conclusion, embryos and their livers displayed differential accumulations of moisture and DM during incubation, and these differences exhibited distinctive associations with various yolk fatty acids.

Key words: carcass fat, carcass protein, embryo, liver, yolk fatty acids

Poultry Science, 1999. 78:143-1442