Guar meal diets as an alternative approach to inducing molt and improving Salmonella enteritidis resistance in late-phase laying hens.

Induced molting of laying hens is a practice used by commercial egg producers to increase the productive lifetime of their flock. However, the conventional method of inducing molt, which involves removal of feed, water, or both as well as a reduction in photoperiod to less than a natural day has drawn criticism due to animal welfare and food safety concerns. The objective of this study was to explore the efficacy of diets containing high levels of guar meal (GM) in inducing molt and reducing susceptibility to Salmonella Enteritidis colonization in late-phase laying hens. Late-phase (68 wk old) Lohmann laying hens were either full-fed standard laying hen diets (nonmolted control), induced to molt by feed withdrawal, or full-fed standard laying hen diets containing 20% GM with or without 250 units/kg of mannanase Hemicell supplementation. On the fourth day of treatment, all hens were orally challenged with SE (1.65 x 10(7) cfu). Hens were killed and evaluated for Salmonella colonization and differences in organ weights 5 d postinoculation. Salmonella Enteritidis present in crop, liver, ovary, and cecal contents were significantly reduced by feeding GM with enzyme supplementation compared with feed withdrawal hens. No significant differences were observed in reproductive tract weights of molted groups, although a difference in liver weight was detected. Results indicate that feeding diets containing 20% GM are as effective as complete feed withdrawal with respect to inducing molt with the added benefit of improved resistance to Salmonella Enteritidis colonization and translocation.

Use of guar by-products in high-production laying hen diets.

A 5x5 Latin square experiment was conducted to evaluate the effect of feeding low concentrations of guar germ or a combination of guar germ and hull (guar meal) in high-production laying hen diets. A total of 125 Lohmann laying hens (21 wk old) of similar BW were randomly assigned to 5 blocks. Each block was divided into 5 experimental units, consisting of 5 hens per unit. Hens were fed either a nonguar control diet, or 1 of 4 diets containing either 2.5 or 5% guar germ, or 2.5 or 5% guar meal over a 20-wk trial period (five 4-wk periods). No significant differences were observed when feeding either 2.5 or 5% guar germ or meal (P>0.05) on hen-day egg production or feed consumption. Significant differences in egg weight, total egg mass per hen, and feed conversion ratio were detected in hens fed 2.5% guar meal, whereas they remained unchanged for diets containing either level of guar germ or 5% guar meal. Feeding either level of guar germ or guar meal did not affect shell quality (shell thickness, egg breaking force, and specific gravity), Haugh units, or egg yolk color (L*, a*, b*). The results showed that both guar germ and guar meal can be fed to high-production laying hens at up to 5% without adverse effects on laying hen performance.

Effects of guar meal by-product with and without beta-mannanase Hemicell on broiler performance.

Guar gum production yields a high protein guar meal that can be subdivided into germ and hull fractions. Feeding high concentrations of guar meal reduces body weight and feed efficiency in chickens due to the presence of a residual guar gum. Two experiments determined the upper feeding levels of guar meal and the hull and germ fractions in broiler chickens. An industrial source beta-mannanase (Hemicell) also was fed in combination with guar meals. Experiment 1 utilized a 3 x 4 factorial design to feed broiler chickens diets containing guar germ, guar hull, or guar meal at 4 levels (2.5, 5.0, 7.5, and 10.0%) compared with a negative control diet. Results indicated that any of the 3 guar meals could be fed at a 2.5% dietary inclusion rate without adversely affecting broiler chicken growth to 6 wk of age. In experiment 2, a 4 x 2 factorial design consisting of the 3 by-products meals at 5% inclusion and soybean meal control with and without enzyme tested whether Hemicell could increase inclusion rates without decreasing broiler growth or feed consumption to 6 wk of age. Addition of Hemicell to feed had no effect on measures of growth in chickens fed the control diet. Hemicell significantly improved feed:gain ratio of diets containing 5% of each fraction of guar meal versus the untreated diets. Feed:gain ratio for the Hemicell-treated 5% germ fraction diet was improved to control diet levels. Results indicated that the upper feeding level of guar meal and germ and hull fraction of guar meal is 2.5%, and addition of beta-mannanase (Hemicell) increases the upper feeding level for the germ fraction to 5%.

Egg storage period and weight effects on hatchability of ostrich (Struthio camelus) eggs.

We studied the affects of storage period and egg weight on the hatchability of 314 ostrich (Struthio camelus) eggs. Eggs were stored at 20 degrees C and 65% RH before incubation at the Poultry Research, Teaching and Extension Center at Texas A&M University (College Station, TX). Eggs were classed by storage period (< or = 5, > 5 < or = 10, > 10 < or = 15, or > 15 < 24 d) and egg weight (< or = 1,450, > 1,450 < or = 1,650, or > 1,650 g) to determine the influence of storage period and egg weight on hatchability, egg weight loss, incubation period, and absolute and relative chick weights. Eggs were incubated at 36.5 to 37.0 degrees C and 25% RH through 38 d of incubation and 36 degrees C and 30% RH thereafter. Mean egg weight loss was greater from eggs of the longest storage period group (> 15 < 24 d) at 21 or 38 d when compared with eggs of the shorter storage periods, but there were no differences at 7, 14, or 28 d among all storage period groups. Mean hatchability was higher in eggs stored < or = 10 d than eggs stored > 15 < 24 d, but hatchability of eggs stored >10 < or = 15 d was not different from eggs stored < or = 10 d or > 15 < 24 d. Incubation period was longer, and absolute and relative weights were higher in eggs stored >15 d than was observed in eggs stored < or = 15 d. Negative correlations were detected between egg weight and moisture loss at 38 d (-0.55) and between hatch time and moisture loss (-0.25). Hatchability was higher in small eggs than medium eggs (< or = 1,650 g). A positive correlation was observed between chick and egg weights (0.84). The results indicated that storage period and egg weight affected egg weight loss. Our results suggested that the most effective storage period was less than 15 d to maintain hatchability for ostrich eggs when incubated at 36.5 to 37.0 degrees C with 25% RH.

Incubation temperature for ostrich (Struthio camelus) eggs.

The impact of incubation temperature on egg weight loss, embryonic mortality, incubation period, hatchability, and chick weight in 394 ostrich (Struthio camelus) eggs was studied. Eggs were obtained from 3 farms in Texas. Three incubation temperatures (36.5, 37.0, or 37.5 degrees C) with relative humidity ranging from 20 to 30% were used. Results showed that incubation of fertile eggs at 36.5 degrees C increased hatchability and incubation period in comparison with other treatments. The incidence of dead in shell and total dead embryos was increased at 37.5 degrees C when compared with 36.5 degrees C. No differences in hatchability, incubation period, dead-in-shell embryos, and total dead embryos were observed between eggs incubated at 37.0 or 37.5 degrees C. Neither chick weight nor egg weight loss at 7, 14, 28, or 38 d of incubation was affected by incubation temperature, but egg weight loss at 21 d was lower for eggs incubated at 37.5 degrees C than for the other treatments. Results show that the most effective incubation temperature for the ostrich is lower than the most effective incubation temperature for most bird species.

Guar meal germ and hull fractions differently affect growth performance and intestinal viscosity of broiler chickens.

High concentrations of guar meal in poultry diets deleteriously affect growth, feed intake, and digesta viscosity. These effects are attributed to residual gum in the meal. A 2 x 5 factorial experiment investigated the impacts of two guar meal fractions (germ and hull) at five inclusion levels (0, 2.5, 5.0, 7.5, and 10.0%) on intestinal viscosity, measures of growth, and feed conversion in broiler chickens fed to 20 d of age. Growth and feed conversion ratio were not affected by inclusion of as much as 7.5% of the germ fraction into poultry diets, while inclusion of the hull fraction reduced growth at all concentrations. The hull fraction increased intestinal viscosity at all inclusion levels fed, although feed conversion was not affected until the inclusion rate exceeded 5.0%. The germ fraction significantly increased intestinal viscosity at 7.5 and 10% inclusion rates. When germ fraction was fed, relative organ weights remained constant through all concentrations except for the ventriculus and duodenum at 7.5 and 10% inclusion levels. Relative pancreas weight was significantly increased at the 10% level of the hull fraction. Increases in intestinal viscosity corresponded with growth depression. These results suggest that residual gum was responsible for some deleterious effects seen when guar meal was fed. The germ fraction was a superior ingredient when compared with the hull fraction. The guar meal germ fraction constituting as much as 7.5% of the diet supported growth and feed conversion measures similar to those observed with a typical corn-soybean poultry ration.

Effect of early feed restriction on reproductive performance in Japanese quail (Coturnix coturnix japonica).

Reproductive performance of quail (Coturnix coturnix japonica) was evaluated following feed restriction (100, 85, and 70% of ad libitum) between 2 to 5 wk of age with three replicates of 12, 2-wk-old chicks per replicate. Body weight, feed conversion, and leucocyte distribution were measured during feed restriction. After experimental feed treatment, BW, age at first egg, egg production, fertility, hatchability, and embryonic mortality were evaluated from five replicates of two females and one male per treatment. Feed-restricted female chicks had lower BW from 3 to 5 wk of age, but male weights were depressed only during the most severe restriction at 4 and 5 wk. No treatment differences were observed among BW within a sex from 6 to 13 wk. Body weights at first egg were significantly heavier for females fed 70% ad libitum than for birds on other treatments. Fertility, age at first egg, feed conversion, egg production, and egg weight were unaffected by feed restriction. Although hatchability was unaffected by feed restriction, percentage of late dead and total dead embryos were significantly reduced in eggs from restricted quail. Thirty quail fed 70% of ad libitum control intake had significantly increased egg specific gravity. Feed restriction increased the percentage of heterophils and basophils and the heterophil/lymphocyte ratio, whereas the percentage of lymphocytes and eosinophils decreased. Feed can be restricted to 85 or 70% of ad libitum feed intake from 2 to 5 wk of age without detrimentally affecting reproductive parameters between 6 to 13 wk of age.

Effect of acetyl salicylic acid in drinking water on reproductive performance of Japanese quail (Coturnix coturnix japonica).

The impact of acetyl salicylic add (ASA) on reproductive performance during periods of heat stress was studied in Japanese quail (Coturnix coturnix japonica). During a season when daily high temperatures averaged between 34 and 40 degrees C, four treatments each containing four replicates of five males and five females were given 0, 0.5, 1.0, or 1.5 g/L ASA in drinking water from 34 to 45 wk of age. At 39 wk of age control quail were lighter than quail fed ASA. Quail receiving 1.5 g/L ASA exhibited increased fertility, hatchability, and egg production and decreased late dead and total embryonic mortality. Early dead embryos, pips, chick weight, and egg weight were not different among treatments. The lumen of uterovaginal junction sperm host glands (UVJSHG) from control quail was apparently devoid of spermatozoa, whereas quail receiving 1.5 g/L ASA had the greatest apparent accumulation of spermatozoa. Control caudal infundibulum host glands (CPOI) were devoid of spermatozoa in contrast with CPOI from quail receiving ASA. Results show that UVJSHG lumens from quail receiving 1.5 g/L ASA had larger inside diameters than other treatment groups. However, the CPOI inside diameter and the outside diameters of both UVJSHG and CPOI were not affected by ASA. Adding 1.5 g/L ASA to the drinking water of quail under heat stress improved body weight, fertility, hatchability, embryonic mortality, egg production, egg specific gravity, and sperm storage capacity.

Effect of feeding time on the reproductive performance of Japanese quail (Coturnix coturnix japonica).

Several feeding regimens are applied to improve performance of fertile egg production during times of heat stress. During a period of heat stress (34 to 36 degrees C), two feeding periods were used to measure the impact of feeding time on reproductive performance of Japanese quail (Coturnix cotunix japonica) between 44 and 60 wk of age. Each feeding time treatment had 25 individually caged male and female pairs. Quail were fed ad libitum between 0600 to 1400 or 1400 to 2200 h daily. Results indicated that feeding between 0600 to 1400 h reduced BW, fertility, hatchability, egg production, and egg specific gravity when compared with the effects of feeding between 1400 to 2200 h. Feeding time had no effect on total embryonic mortality, egg weight, or the period between subsequent ovipositions. The different feeding times affected the distribution curve of oviposition over time. An instrument designed to record oviposition time is described. Results showed that selection of the time of day for application of an 8-h restricted feeding regimen affected BW, fertility, hatchability, egg production, egg specific gravity, and oviposition time in Japanese quail.

beta-Mannanase ameliorates viscosity-associated depression of growth in broiler chickens fed guar germ and hull fractions.

High concentrations of guar meal in broiler chicken diets reduce body weight and feed efficiency. The increased intestinal viscosity that is responsible for reduced measures of performance results from residual guar gum present in guar meal. Two experiments were designed to study the effects of 2 guar meal fractions at 3 different concentrations, germ (0, 5.0, and 7.5%) and hull (0, 2.5, and 5.0%), and the effectiveness of a beta-mannanase at three levels (0, 1x, and 4x; 1x = 1.09 x 10(5) units/ kg) on broiler growth and feed conversion. Growth and performance were measured as a function of intestinal viscosity. Addition of the germ fraction to rations did not reduce body weight, although feed conversion ratio was increased at 7.5% of the diet. Intestinal viscosity also increased significantly at this level. Enzyme addition significantly reduced intestinal viscosity. Due to an interaction that was present between hull and enzyme concentration, each treatment was compared separately. Inclusion of the hull fraction significantly reduced body weight at both levels of inclusion and increased feed conversion ratio at 5% inclusion. Addition of the enzyme significantly increased body weight and reduced feed conversion ratio in diets containing guar hull fractions. Supplementation of beta-mannanase to feeds containing either fraction of guar meal reduced intestinal viscosity and alleviated the deleterious effects associated with guar meal feeding.

Abdominal fat pad mass reduction by in ovo administration of anti-adipocyte monoclonal antibodies in chickens.

The effect of in ovo administration of antiadipocyte monoclonal antibodies (MAb) on growth and adipose tissue development in chickens was investigated. In Trial 1, 60 fertilized eggs from layer-type chickens were injected into allantoic circulation with different amounts of MAb against chicken adipocyte plasma membranes (0, 0.05, 0.1, 0.2, and 0.4 mg) on Day 15 of embryogenesis. In Trial 2, 180 fertilized broiler eggs were injected into allantoic circulation with 0.2 mg MAb on Day 15 of embryogenesis. In Trial 1, high doses (0.2 and 0.4 mg) of MAb in in ovo injection reduced (P < or = 0.05) abdominal fat pad weight without affecting total body weight at 42 d of age. Only the highest dose (0.4 mg) significantly reduced hatch rate. In Trial 2, adipose tissue (pectoral, femoral, and abdominal), major organ (heart, liver, and spleen), and total body weights at 14 d of age were not affected by in ovo injection. Hatch success rate of eggs was not significantly different among treatments. However, by 6 wk of age, in ovo injection of MAb significantly reduced (P < or = 0.05) abdominal fat pad weight by more than 28%. This relative fat pad mass reduction occurred without affecting femoral or pectoral fat tissues. Total body weight and feed intake were not affected among treatments. Our experiments demonstrated for the first time that in ovo administration of anti-adipocyte MAb on Day 15 of embryogenesis reduced the chicken abdominal fat pad mass by 42 d of age without affecting growth or body weight.

Inhibition of chicken adipocyte differentiation by in vitro exposure to monoclonal antibodies against embryonic chicken adipocyte plasma membranes.

Specific monoclonal antibodies (MAb) against adipocyte precursor antigens were developed. These MAb identified adipocyte precursors and reduced their prominence in primary stromal-vascular (SV) cultures by complement-mediated cytotoxicity or by inhibition of differentiation. Binding of antibodies to chicken adipocyte precursors was confirmed by immunofluorescence visual examination following secondary exposure to fluorescein isothiocyanate-conjugated goat antimouse IgG. Cross-reaction of MAb with muscle, kidney, liver, fibroblasts, and other cell types not containing lipid droplets was not observed in primary cultures. Adipocyte precursors were obtained from 18-d chick embryo adipose tissue by collagenase digestion to investigate complement-mediated cytotoxicity of preadipocytes. Cultures were maintained in Medium 199 with 5% fetal bovine serum (FBS) for 4 d. Subsequently, Medium 199 supplemented with 10% chicken serum initiated adipocyte differentiation. At Day 5 postinoculation, individual or combinations of MAb were administered to preadipocyte cultures; rabbit complement was added 30 min later. After 1 d of incubation, four of the six individual MAb with complement significantly (P < 0.05) reduced the number of fat cell clusters that developed by 40 to 60%. These MAb in the presence of complement also significantly (P < 0.05) reduced mean cell width and apparent cell area or cell cluster area of lipid-containing cells. Neither MAb nor complement alone reduced fat cell cluster number, cell size, or cluster size. Treatment with pools of two and four MAb decreased the total amount of MAb protein required to reduce fat cell cluster number. Four antibodies, alone or in combination, reduced fat cell cluster development in a complement-dependent manner.

Fatty acid turnover rates in the adipose tissues of the growing chicken (Gallus domesticus).

The purpose of this study was to investigate the mobility of fatty acids in adipose tissue of the chicken and to determine whether adipose tissue dynamics are altered by dietary repartitioning agents. To this end, the turnover rates of fatty acids and triglycerides were estimated in adipose tissue of growing chicks by using isopentadecanoic acid (IPDA) and elaidic acid (EA) as marker dietary fatty acids. The half-life of IPDA in abdominal and sartorial adipose tissues of birds over 6 to 10 wk of age were 20 +/- 4 and 23 +/- 6 d, respectively. The half-life for the remaining total carcass lipids was 23 +/- 3 d. The corresponding half-life for EA in abdominal fat tissue of birds over 2 to 7 wk of age was 18 +/- 3 d, a half-life not significantly different from the IPDA half-lives. On the other hand, a thyromimetic repartitioning agent (L-94901) fed to birds at the 2 ppm level from 2 to 7 wk of age significantly decreased the half-life of EA in abdominal fat tissue to 6 +/- 2 d. The data suggest that fatty acids were released from a more labile adipose site and subsequently reincorporated into abdominal and sartorial tissues and that fat mobilization occurred at the same time as did adipose tissue deposition in the growing chicken.

A Peroxidase Catalyzed Chemical Dip for the Reduction of Salmonella on Chicken Breast Skin.

A peroxidase catalyzed Chemical dip (PC) was tested for effectiveness in reducing Salmonella choleraesuis serovar typhimurium and S. choleraesuis serovar arizonae from breast skin surfaces of broilers. Salmonella counts on breast skin inoculated with a high level or low level of either serovar were significantly decreased after 30 min in water-dipped and PC treatments. A residue analysis for the Chemical components of the PC, peroxidase, peroxide, iodide, and iodine were performed on poultry carcass skin and muscle tissue treated with PC and compared to non-PC-treated samples. Peroxidase catalyzed Chemical dip raw skin tissue had the highest peroxidase content, but peroxide content in the skin was lowered in both raw and cooked PC-treated skin tissue. Muscle peroxide content was higher in cooked untreated and PC raw than the water-dipped or cooked PC samples. Skin iodide was higher in water and PC raw-treated samples than control raw samples, while muscle iodide was higher in water raw than all other treatments. Tissue iodine was at levels less than the detectable limit of 25 mg/g for all treatments.

Factors affecting insulin responsiveness of triglyceride synthesis in incubated chicken hepatocytes.

A technique was developed to isolate and incubate hepatocytes from 4-day-old chickens. Hepatocytes incubated in serum-free medium containing 1 ng chicken insulin/ml had greater rates of triglyceride (TG) synthesis than insulin-unexposed cells. Greater concentrations of insulin enhanced TG synthesis. Addition to medium of a supplement containing several hormones greatly improved insulin responsiveness of TG synthesis in hepatocytes compared with cells not incubated in supplemented medium. The medium supplement did not affect TG synthesis in hepatocytes incubated in the absence of insulin. The presence, compared with the absence, of triiodothyronine in the medium supplement improved insulin responsiveness of TG synthesis. In hepatocytes incubated in supplemented medium, increasing chicken insulin concentrations augmented malic enzyme activity. Hepatocytes incubated in supplemented medium containing bovine insulin had lesser rates of TG synthesis than cells incubated with similar concentrations of chicken insulin. To determine whether insulin responsiveness of TG synthesis is affected by age of chicken, hepatocytes from 4-, 11-, and 74-day-old chickens were incubated in supplemented medium. Responsiveness of TG synthesis to chicken insulin progressively decreased in hepatocytes from older chickens. Results indicate that hepatocytes isolated from 4-day-old chickens and incubated in supplemented medium are responsive to dilute insulin concentrations and may be useful to investigate the biochemical effects of this hormone.

The effect of increasing photoperiod and food restriction in sexed broiler-type birds. I. Growth and abdominal fat cellularity.

1. Sexed broiler-type chicks were raised either under a continuous (CON) 23 h Light (L) and 1 h Dark (D) schedule or an increasing photoperiod (INC) consisting of an initial 6 h L and 18 h D which increased by 4 h L per week from 14 to 35 d of age after which a 23 L:1D was maintained to 49 d of age. 2. From 5 to 11 d of age birds were fed either: ad libitum (AL), energy intake (kJ ME) restricted to 9.414 x gBW0.67 (R1) or energy intake (kJ ME) restricted to 6.276 x gBW0.67 (R2). Food intake was ad libitum at all other times. 3. Food restriction reduced growth to 49 d of age although some compensatory growth did occur. Food efficiency was not significantly affected by restriction. 4. Although abdominal fat pad weight was significantly reduced for R2 compared to AL, this was not significant on a percentage body weight basis. 5. Adipocyte number in the abdominal fat pad was similar for AL, R1 and R2, but concomitant with a smaller fat pad weight, R2 showed reduced adipocyte volume compared to AL. 6. INC birds were lighter at 21 d of age, but body weights were equivalent to CON by 42 d of age. 7. Abdominal fat pad weight was some 10% larger at 49 d of age for INC birds. Adipocyte volume was unaffected, the increase in adipocyte being entirely caused by an increase in adipocyte number in INC birds.

The effect of increasing photoperiod and food restriction in sexed, broiler-type birds. II. Plasma thyroxine, triiodothyronine, insulin-like growth factor-I and insulin.

1. Sexed broiler-type chicks were raised either under a continuous (CON) 23 h light (L) and 1 h dark (D) schedule or an increasing photoperiod (INC). From 5 to 11 d of age birds were fed either: ad libitum (AL), energy intake (kJ ME) restricted to 9.414 x gBW0.67 (R1) or energy intake (kJ ME) restricted to 6.276 x gBW0.67 (R2). 2. Blood samples were taken at 4, 7, 11, 14 d of age and weekly thereafter to 49 d of age. Plasma thyroxine (T4), triiodothyronine (T3), insulin-like growth factor-I (IGF-I) and insulin were determined. 3. CON birds had elevated plasma T3 concentrations to 21 d of age, and greater plasma T4 concentrations at 11 and 21 d of age concurrent with greater food intake. Elevated plasma T3 concentrations in INC birds at 28 d of age coincided with lower plasma IGF-I concentrations at a time when growth and food intake were greater than CON birds. 4. Food restriction elevated plasma insulin and T4 but depressed plasma T3 and IGF-I. Plasma T3 was greater for food-restricted birds at 21 d of age, but subsequently, was generally lower than ad libitum-fed birds which may account for a lack of complete 'catch-up' in growth. 5. Plasma T3 was higher in females at 11 d of age when growth was equivalent for both sexes. From 28 to 42 d, when sex differences in growth became most apparent, plasma T3 was greater in males.

Adipose cellularity in Gallus domesticus: investigations to control body composition in growing chickens.

The domestic chicken, Gallus domesticus, is recognized as an efficient source of lean meat. Genetic selection has resulted in large body size strains that grow rapidly. Concomitant with development of these desirable characteristics is increased abdominal fat deposition and altered body composition. Adipose cellular development in different genetic groups shows that abdominal adipocyte cell number as a proportion of body mass decreases as body size increases, concurrent with increased adiposity. Adipocyte hypertrophy explains a large proportion of the variation in abdominal fat percentage. Growth hormone is correlated with the number and size of abdominal adipocytes across genotype, sex and age. Adipose tissue development and body composition are affected by hormone levels in growing chickens. Possible approaches to modulate fat deposition and adipose cellularity in poultry are reviewed.

Plasma lipoprotein profiles in broiler chicks (Gallus domesticus): effects of early overfeeding.

1. Twenty-eight day old broiler chicks gavage fed for 22 days consumed 40% more feed and gained 100-110 g more than control birds. 2. Normal feeding resumed on day 41, by day 63 feed intakes and body weights of overfed and control birds were equal. 3. Moderate differences in lipid compositions of LDL and VLDL were observed at 41 and 50 but not at 63 days. 4. In contrast to mammals where early over feeding predisposes to adult obesity, lipoprotein profiles and ad lib feeding patterns of chicks are not readily altered by dietary measures.