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PubMed2004

N(omega)-nitro-L-arginine methyl ester (L-NAME) amplifies the pulmonary hypertensive response to endotoxin in broilers.

The pulmonary hypertensive response to bacterial lipopolysaccharide (LPS, endotoxin) varies widely among individual broilers, leading to the suggestion that innate variability may exist in the proportions or profiles of chemical mediators released during the ensuing inflammatory cascade. LPS induces the expression of nitric oxide synthase (iNOS), which produces the vasodilator nitric oxide (NO) to modulate the responses to concurrently produced vasoconstrictors. In experiment 1, broilers were given the NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME), followed by a supra-maximal dose of LPS while the pulmonary arterial pressure was recorded. In experiment 2 the cardiac output also was recorded before and following the i.v. injection of L-NAME. In both experiments, injection with L-NAME modestly increased the pulmonary arterial pressure when compared with control values, confirming previous reports that tonic/basal NO synthesis is required to promote flow-dependent pulmonary vasodilation in chickens. This response to L-NAME occurred in spite of a tendency for cardiac output and stroke volume to decline and, therefore, can be attributed to pulmonary vasoconstriction (an increase in the pulmonary vascular resistance) rather than an increase in pulmonary blood flow. When L-NAME was used to block NO synthesis induced by LPS, an early peak of pulmonary hypertension was revealed that rarely develops in broilers in the absence of L-NAME, and that has been correlated with the release of platelet activating factor and thromboxane A2 in mammals. The control group responded to LPS with a delayed-onset pulmonary hypertension that was typical in timing, amplitude, and duration of the responses previously observed in broilers and that has been attributed to endothelin-mediated thromboxane A2 synthesis in mammals. This delayed-onset pulmonary hypertensive response to LPS was longer in duration and higher in amplitude in the L-NAME group when compared with the control group. These observations are consistent with the hypothesis that NO modulates the responses to vasoconstrictors released concurrently during the LPS-mediated inflammatory cascade. Inhibition of NOS by L-NAME apparently reduced the modulatory influence of NO and exposed a more dramatic pulmonary hypertensive response to LPS.

Animals↗

PubMed2004

Growth performance and nitrogen excretion of broilers using a phase-feeding approach from twenty-one to sixty-three days of age.

Two experiments were conducted to assess effects of phase-feeding (PF) on broilers from 21 to 63 d. Experiment 1 evaluated the impact of PF on growth performance, whereas experiment 2 assessed the effects of PF on CP intake and nitrogen excretion. Diets were formulated using recommendations from NRC or linear regression equations. Two PF treatments were prepared: standard (PF) and low (PF10), in which predicted Lys, sulfur amino acid, and Thr recommendations were reduced by 10%. For PF and PF10, 2 diets (high-nutrient and low-nutrient density) were blended in variable quantities to produce rations matching predicted requirements. An NRC grower and finisher diet or a series of PF and PF10 diets that were switched every other day were fed. In experiment 1, weight gain and feed efficiency were improved (P < 0.05) by PF10 relative to broilers fed the NRC-based diet. Crude protein intake was reduced (P < 0.05) by PF10 relative to broilers fed NRC and PF diets. No differences (P > 0.05) in percentage carcass composition were observed when broilers were fed PF or PF10 diets. Significant reductions (P < 0.05) in dollars per kilogram of weight gain were noted with PF regimens. In experiment 2, PF and PF10 diets reduced (P < 0.05) CP intake and nitrogen excretion from 43 to 63 d. Results indicate that PF regimens may substantially reduce dietary costs and may have environmental benefits.

Aging↗

PubMed2004

Early postmortem injection and tumble marination effects on broiler breast meat tenderness.

Several processors use inline injection and tumble marination practices to decrease labor costs and product handling. However, the stimulation of this early postmortem (PM) muscle may cause increased toughness. Therefore, the objective of this study was to compare marination of early PM meat by using injection, vacuum tumbling, or both to determine their effects on tenderness of broiler breast fillets. Breast fillets from 45 broilers were deboned at 3 h PM and injected, tumbled (30 min, 635 mmHg, 14 rpm), or injected + tumbled with a 10% solution of 0.54%. NaCl + 0.42% sodium tripoly phosphate (STPP). Nonmarinated controls deboned at 3 and 6 h PM were also included. Shear value, sarcomere length, and cook loss were determined on each of the fillets. The control and tumbled fillets had the highest shear value compared with the remaining 3-h treatments. The injected + tumbled and tumbled fillets had the highest cook loss followed by 3-h control and injected treatments. Tumble marination at 3 h PM produced significantly tougher meat then the injection treatment. Experiment 2 was conducted to test marinade penetration through the fillets because penetration could have affected the results of the previous study. Broiler breast fillets were deboned from 60 broilers at 3 h PM and were vacuum tumbled (30 min, 635 mmHg, 14 rpm) with a 15% solution of 0.54% NaCl and 0.42% STPP. We determined shear value and cooked meat moisture of the fillets and sodium ion migration into the fillets. Although there were no significant differences in shear value between control and tumbled fillets, the cooked meat moisture was significantly higher in tumbled fillets when compared with the controls. Sodium ion concentration was significantly higher on the surface (especially the lateral surface) of the fillets when compared with the center, which suggested some uneven distribution.

Animals↗

PubMed2004

Evaluation of microbial phytase in broiler diets.

Two trials were conducted to evaluate the efficacy of a new microbial phytase (Phyzyme XP) for broiler chicks. Trial 1 used 192 8-d-old male broilers in a 14-d trial to assess growth and nutrient utilization. Dietary treatments (221.9 g/kg CP) included a positive control [5.0 g/kg nonphytate P (NPP)], negative control (1.2 g/kg NPP), and negative control plus 500 or 1,000 phytase units/kg of diet. Phytase addition increased weight gain, feed intake, feed efficiency, and tibia and toe ash (linear, P < 0.01) with tibia ash also responding quadratically (P < 0.05). Apparent ileal digestibility of P (linear and quadratic, P < 0.05), tryptophan, and valine (linear, P < 0.05) also increased. Linear and quadratic responses were observed for retention of DM, nitrogen, P, and several amino acids (P < 0.05) with added phytase. Trial 2 utilized 576 1-d-old male broilers over a 42-d period to evaluate growth performance. Diets were formulated for starter (222.7 g/kg CP) and grower (201.5 g/kg CP) phases and included a positive control (starter and grower, 5.0 and 3.8 g/kg NPP, respectively); negative control (starter and grower, 2.4 and 1.8 g/kg NPP, respectively); negative control plus 500, 750, or 1,000 phytase units/kg; and negative control plus 500 phytase units/kg of Natuphos phytase. Phytase increased weight gain and feed intake (starter, grower, overall) as well as feed efficiency during the starter period (linear, P < 0.05). Feed intake was also improved during the grower period and overall (quadratic, P < 0.05). Tibia and toe ash of birds fed for the first 21 d increased (linear, P < 0.05) with tibia ash also increasing quadratically (P < 0.05). Overall, tibia and toe ash were improved due to phytase addition (linear and quadratic, P < 0.05). In conclusion, this microbial phytase, derived from Escherichia coli and expressed in Schizosaccaromyces pombe, elicited improved growth performance, bone mineralization, and P utilization in broiler chicks.

6-Phytase↗

PubMed2004

The effect of phytase enzyme and level on nutrient extraction by broilers.

Three experimental phytase enzyme preparations derived from the same Escherichia coli gene but produced in Saccharomyces cerevisiae (A), Pichia pastoris (B), and Pseudomonas fluorescens (C) were compared with a commercial enzyme preparation by addition to wheat-soybean meal diets fed to broiler chicks. A positive control diet contained sufficient available phosphorus for normal broiler growth and a negative control diet was phosphorus deficient. The 4 enzymes were added to the negative control diet at 3 levels each (150, 450, and 1,250 U/kg), and all diets were pelleted above 80 degrees C. Broiler chicks were fed experimental diets from 4 to 21 d. Chick performance and nutrient digestibility showed that the pel leting process inactivated enzymes A and C and the commercial enzyme. When added to the negative control diet, enzyme B had positive effects on broiler performance and calcium and phosphorus digestibility, and increasing levels of enzyme had greater positive effects. Enzyme B also increased the AME and protein digestibility over those of either control diet. These results suggest that enzyme B was not inactivated by pelleting above 80 degrees C, whereas the other enzymes were.

6-Phytase↗

PubMed2005

Use of water spray and extended drying time to lower bacterial numbers on soiled flooring from broiler transport coops.

Broiler transport coops soiled with Campylobacter-positive feces have been shown to facilitate cross-contamination of broilers. Washing and sanitizing coop surfaces do not always effectively eliminate bacteria. The objective of this study was to examine drying as a means of lowering bacterial numbers on transport coop flooring. Small squares (5 x 5 cm) of fiberglass flooring from transport coops were intentionally contaminated with 1 g of Campylobacter-positive broiler gut contents. Soiled floor squares were sprayed with water and allowed to dry for 15 min, 24 h, or 48 h. Unsprayed squares were examined at each time period as controls. All squares were sampled by cotton-tipped applicators that were cultured for Campylobacter, coliforms, and Escherichia coli. Sampling of unsprayed squares at 15 min yielded 7.3 log cfu of Campylobacter, 6.2 log cfu of coliforms and 5.9 log cfu of E. coli per floor square. Water spray alone resulted in a significantly lower number of organisms recovered: 4.1 log cfu Campylobacter, 3.6 log cfu coliform, and 3.2 log cfu E. coli per floor square. When water spray was followed by a 24-hour drying period, no Campylobacter, coliforms, or E. coli were detected on the floor surface. However, allowing unsprayed soiled flooring to simply dry for 24 or 48 h also resulted in no recovery of Campylobacter and very low numbers of coliforms and E. coli. A 24- or 48-hour drying period for fecal matter on broiler transport cage flooring may be a viable method to lower bacterial numbers on these surfaces.

Animals↗

PubMed2005

Carbohydrases, protease, and phytase have an additive beneficial effect in nutritionally marginal diets for broiler chicks.

To investigate the additive effects of xylanase, amylase, protease, and phytase in the diets of broiler chickens, a study was conducted using 1,152 growing broiler chicks (8 treatments with 12 replicate pens of 12 chicks). The birds were fed a corn/soybean-based negative control (NC) diet that was formulated to be nutritionally marginal in terms of metabolizable energy, Ca, and P. A nutritionally adequate positive control (PC) diet was fed for comparison. The NC diet was supplemented with phytase; a cocktail of xylanase, amylase, and protease (XAP); or a combination of phytase and XAP at 100 or 200 mg of each enzyme/kg (200 mg of XAP/kg provided a guaranteed minimum of 300 U of xylanase, 400 U of amylase, and 4,000 U of protease/kg; 200 mg of phytase/kg provided a guaranteed minimum of 1,000 U of phytase/kg). Growth performance, ileal digestible energy (IDE), and the digestibility coefficients of N, Ca, P, and DM were calculated. Individually and in combination, both phytase and XAP improved (P < 0.05) gain-to-feed ratio compared with the NC diet, particularly at the highest inclusion concentration. Body weight gain followed a similar trend, showing an improvement of approximately 6 to 7% with either enzyme individually and a 14% improvement with a combination of phytase and XAP. The effect of enzymes on IDE and nutrient digestibility coefficients was not as marked, but a 165 kcal/kg reduction in IDE was noted between the NC and PC diets, and a combination of phytase and XAP improved IDE by >100 kcal/kg. It can be concluded that the use of phytase and XAP individually in a corn/soybean meal-based diet is effective in improving nutrient digestibility and performance of broilers fed nutritionally marginal diets. Furthermore, there may be an additive effect of phytase and XAP on broiler performance, giving a cost-effective nutritional strategy for the profitable production of poultry products.

6-Phytase↗

PubMed2005

Comparison of broiler performance when fed diets containing corn grain with insect-protected (corn rootworm and European corn borer) and herbicide-tolerant (glyphosate) traits, control corn, or commercial reference corn--revisited.

A 42-d feeding experiment with growing Ross x Ross 508 broilers showed that the nutritional value of insect-protected and herbicide-tolerant corn was comparable to that of the genetically similar control and 5 commercial reference corn hybrids. MON 88017 provides protection from feeding damage by coleopteran pest corn rootworm and is tolerant to the action of glyphosate, the active ingredient in the Roundup family of agricultural herbicides. MON 88017 x MON 810 was developed by the traditional breeding of MON 88017 with MON 810, which provides protection from the European corn borer and other lepidopteran pests. A randomized complete block design was used with 8 dietary treatments in each of 5 replicated blocks of pens. No differences among diets were observed (P > 0.05) in performance (final live weights, feed intake, feed conversion, and adjusted feed conversion), carcass yield (chill, fat pad, breast, thigh, wing, and drum weight), or percentage of moisture, protein, and fat in breast meat and moisture and fat in thigh meat. Thigh protein was similar (P > 0.05) in broilers fed diets containing MON 88017 x MON 810 and conventional control or all commercial reference corns; however, differences (P < 0.05) were noted for the percentage of thigh protein among broilers fed the control and 2 of the 5 reference diets, attributable to biological variability among the conventional corn hybrids. Broilers overall performed consistently and had similar carcass yield and meat composition when fed diets containing MON 88017 or MON 88017 x MON 810 as compared with those fed the conventional control and commercial diets, supporting a conclusion of nutritional equivalence.

Animal Feed↗

PubMed2005

Comparison of broiler performance when fed diets containing corn grain with insect-protected (corn rootworm and European corn borer) and herbicide-tolerant (glyphosate) traits, control corn, or commercial reference corn.

Adipose Tissue↗

PubMed2005

Effects of dietary phosphorus, phytase, and 25-hydroxycholecalciferol on performance of broiler chickens grown in floor pens.

Three 49-d experiments (Exp 1, 2, and 3) with broilers in floor pens were conducted to test the applicability of nonphytin phosphorus (NPP) requirements and the NPP-sparing effect of phytase (PHY) and 25-hydroxycholecalciferol (25D) determined previously in battery Exp. Six dietary NPP treatments were tested using a 4-phase feeding program. Treatments 1 to 6 were NRC (1994) NPP (C); University of Maryland (UMD) NPP; UMD NPP - 0.064% (UMD+PHY); UMD NPP - 0.09% (UMD+PHY+25D); NRC - 0.10% (C+PHY), and 90% UMD NPP (NC), respectively. Treatments 3, 4, and 5 had 600 U of PHY/kg of diet. Treatment 4 also had 70 microg of 25D/kg of diet; NPP concentrations were reduced to account for the sparing effect of these additives. No differences in hatch to 49 d BW were observed between treatments in Exp 1 and 2, and only in Exp 3 were the BW of the NC broilers (2.86 kg) different (P < 0.05) from those fed the C, UMD, and UMD+PHY treatments (2.96, 2.94, and 2.98 kg, respectively). Cumulative NPP consumption per bird was lowest (P < 0.05) for broilers fed the UMD+PHY+25D treatment (8.65 g in Exp 3) compared with those fed the C, NC, UMD, and UMD+PHY treatments (18.19, 10.60, 13.63, and 11.01 g, respectively for Exp 3). Application of any of these treatments reduced total P and NPP consumption compared with C. The results of this series of floor pen Exp validate the UMD NPP recommendations for a 4-phase feed program and the PHY and 25D NPP-sparing effects observed in battery trials without negatively affecting broiler performance.

6-Phytase↗

PubMed2005

Utilization of metabolizable energy by young broilers and birds of intermediate growth rate.

An experiment was conducted to study the utilization of ME by 3 strains of birds with different growth rates: commercial broilers, Plymouth Barred Rocks, and Leghorns. Birds were fed a diet providing 3,100 kcal of ME/kg and 20% CP from 0 to 42 d. ME and nitrogen balance were determined from 10 to 15, 23 to 28, and 37 to 42 d. Energy retained (ER) as fat (ERF) and protein (ERP) were derived from body analyses for each period and group of birds. ERF and ERP were obtained as the difference in values at the end of each period and their respective predicted values based on BW at the beginning of the period. ER, ERF, and ERP per unit metabolic BW were significantly different for broilers vs. the other 2 strains in all periods (P < 0.001). Heat production and ER increased significantly (P < 0.01) for all groups. There was a significant decrease in HP (P < 0.001) over time with no change in ER, ERF, or ERP over time. Age appeared to have no significant effect on ERF/ME regardless of strain. Estimation of maintenance requirements as a function of BW0.75 vs. BW0.60 showed that requirements for broilers per kilogram of BW0.75 are 8% lower compared with estimates based on BW0.60. It seems that energy requirements for maintenance has been underestimated for younger or smaller birds and implies greater apparent efficiency for growth. Because ME intake for maintenance requirements represents a large portion of the ME intake, the results from this experiment could be considered in calculation of energy requirements for growing broilers.

Aging↗

PubMed2005

Nomega-nitro-L-arginine methyl ester (L-NAME) amplifies the pulmonary hypertensive response to microparticle injections in broilers.

We tested the hypothesis that microparticles entrapped within the pulmonary vasculature elicit the production of nitric oxide (NO) in quantities sufficient to modulate the combined impact of physical occlusion plus contemporaneously released vasoconstrictors. In experiment 1, male broilers were given an injection of the NO synthase (NOS) inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME), followed by an intravenous injection of cellulose microparticles while the pulmonary arterial pressure (PAP) and cardiac output (CO) were recorded. When L-NAME was used to block NO synthesis induced by the microparticles, an early peak of pulmonary hypertension was revealed that rarely developed in the absence of L-NAME. The subsequent more prolonged increases in PAP and pulmonary vascular resistance (PVR) were greater in amplitude and duration in broilers pretreated with L-NAME than in broilers in the control group. These amplified responses occurred in spite of a simultaneous reduction in CO, thereby conclusively demonstrating that inhibiting NOS permitted the development of a much more profound increase in the PVR. In experiment 2 the mortality triggered within 48 h after injecting microparticles was evaluated in the presence and absence of L-NAME. The 48 h postinjection mortality more than doubled when L-NAME was combined with microparticle injection doses that otherwise caused relatively low mortality in the absence of L-NAME. Experiment 3 was conducted to determine whether NO contributes to the systemic hypoxemia that develops after microparticles are injected. L-NAME administration had no impact on the magnitude and duration of the microparticle induced decline in the percentage saturation of hemoglobin with oxygen (%HbO2). Evidently hypoxemia per se contributes relatively little to the amplified pulmonary vasoconstriction and 48 h postinjection mortality triggered by microparticle injections in broilers pretreated with L-NAME. These observations indicate that NO modulates the responses to vasoconstrictors released when microparticles become entrapped in the pulmonary vasculature. Inhibition of NOS by L-NAME exposed a more dramatic increase in PVR and pulmonary hypertension leading to enhanced mortality in response to microparticle injections.

Animals↗

PubMed2005

Effect of prebiotic on gut development and ascites incidence of broilers reared in a hypoxic environment.

Modern broilers have been genetically selected for an increased growth rate and improved feed conversion, but they are also more susceptible to ascites. Ascites occurs when there is an imbalance between available oxygen and the oxygen demand of the broiler. We hypothesized that promoting neonatal gut development with a prebiotic, such as Aspergillus meal (Prebiotic-AM), would enhance gut efficiency, decrease the oxygen demand of the gut, and reduce ascites incidence. In this study, we compared the effect of Prebiotic-AM on ascites incidence and gut development in commercial broilers reared at a local altitude (390 m above sea level) and a simulated high altitude (2,900 m above sea level). Half of the birds received a National Research Council recommended corn-soybean ration, and the other half received the same ration supplemented with 0.2% Prebiotic-AM. These 2 groups were further divided into a local altitude group and a simulated high altitude group for a total of 4 treatment combinations. Tissues were collected on d 1, 3, 7, 14, and 21 from the duodenum and lower ileum and placed in 10% buffered formalin for morphometric analysis. At a simulated high altitude, ascites incidence was 68% for birds fed the Prebiotic-AM supplement compared with 92% ascites incidence in birds given the control feed. The simulated high altitude decreased (P < 0.05) gut development, but prebiotic-treated birds reared in hypoxic conditions had similar gut development to control birds reared at local altitude. These data suggest that a feed ration supplemented with Prebiotic-AM may reduce the effect of hypoxia on broiler gut development and ascites incidence.

Altitude↗

PubMed2005

Evaluation of the broiler's ability to adapt to an early moderate deficiency of phosphorus and calcium.

We studied the ability of broiler chickens to adapt to early moderate P and Ca deficiencies by evaluating the impact of feeding different concentrations of P and Ca, from 1 to 18 d, on performance, bone characteristics, and nutrient absorption in the grower (Gr) period (18 to 32 d). Two starter (St) diets were fed from 1 to 18 d: a control (C) diet [0.45% nonphytate P (nPP) and 0.9% Ca] and a low (L) diet (0.30% nPP and 0.6% Ca). On d 19, half of the birds fed the St C diet were switched to a Gr C diet (0.40% nPP and 0.8% Ca), and the other half were switched to a Gr L diet (0.30% nPP and 0.6% Ca), whereas those fed the L diet in the St phase were fed the L diet in the Gr phase, resulting in a total of 3 treatments. Broiler chickens fed the St L diet weighed less (P < 0.05) than those fed the St C diet at 18 d; however, by 23 d they had they caught up to the C-C birds, and no BW differences (P > 0.05) were observed at 28 and 32 d. Feeding the St L diet resulted in decreased (P < 0.05) tibia ash at 18 d, but by 32 d their tibia ash was not different from that of birds fed the St C and Gr L diets. Broilers subjected to P and Ca restriction from hatch to 18 d absorbed more P and Ca during all times sampled than birds fed the St C and Gr C diets or those fed the St C and the Gr L diet. These results demonstrated that modern broilers exhibited a high adaptive capacity when they were exposed to early dietary P or Ca restrictions.

Adaptation, Physiological↗

PubMed2005

Nutritive values of corn, soybean meal, canola meal, and peas for broiler chickens as affected by a multicarbohydrase preparation of cell wall degrading enzymes.

The effect of a new multicarbohydrase supplement of cell wall degrading activities on the nutritive value of corn, soybean meal (SBM), canola meal (CM), and peas for broiler chickens was investigated. Four isoenergetic and isonitrogenous corn (69% corn), SBM (30% SBM, 59% corn), CM (30% CM, 54% corn), and pea (30% peas, 52% corn) diets, without or with enzyme supplementation, were formulated to meet NRC specifications for broiler chickens (except for AME and CP, which were at 95 and 92% of NRC requirements, respectively). The enzyme supplement supplied 1,000 U of xylanase, 400 U of glucanase, 1,000 U of pectinase, 120 U of cellulase, 280 U of mannanase, and 180 U of galactanase per kilogram of diet. Each diet was fed in a mash form to 9 replicate pens of 5 broilers from 5 to 18 d. When compared with the control treatment, enzyme addition to the corn diet improved (P < 0.05) feed-to-gain ratio, whereas the performance of birds fed the other 3 diets was not affected. An increase (P < 0.05) in total tract nonstarch polysaccharides (NSP) digestibility, ileal starch digestibility, and AMEn was observed in birds fed the enzyme-supplemented corn diet. An improvement (P < 0.05) in total tract NSP digestibility, ileal protein digestibility, and AMEn content with enzyme supplementation was observed for the SBM diet. However, nutrient digestibilities and AMEn of CM and pea diets were not affected (P > 0.05) by enzyme addition even though the NSP digestibilities increased significantly (P < 0.05). A significant increase (P < 0.05) in water-soluble NSP and a decrease (P < 0.05) in water-insoluble NSP concentration of ileal digesta was noted for birds fed all 4 enzyme-supplemented diets. It would appear from this study that the nutrient utilization of corn-SBM diet by broilers could be enhanced by using an appropriate multicarbohydrase enzyme supplement. The nutrient encapsulating effect of cell wall polysaccharides in SBM, CM, and peas may not be the only factor responsible for incomplete nutrient utilization. The improvement in feed efficiency and starch availability in birds fed corn diet likely resulted from the cell wall degrading activity of the enzyme supplement.

Animal Feed↗

PubMed2005

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%.

Animal Feed↗

PubMed2005

Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point.

This study examined the effects of varying air velocities vs. a constant air velocity with a cyclic temperature curve of 25-30-25 degrees C and a dew point of 23 degrees C on broilers from 28 to 49 d of age. Four replicate trials were conducted. In each trial, 742 male broilers were randomly allocated to 6 floor pens or 2 air velocity tunnels, with each tunnel consisting of 4 pens. Bird density, feeder, and waterer space were similar across all pens (53 birds/ pen; 0.07 m2/bird). The treatments were control (still air), constant air velocity of 120 m/min, and increasing air velocity (90 m/min from 28 to 35 d, 120 m/min from 36 to 42 d, and 180 m/min from 43 to 49 d). Birds grown in a still air environment gained less weight, consumed less feed, and converted feed less efficiently between 28 and 49 d than birds subjected to moving air (constant or increasing). Growth responses between the air velocity treatments were similar from 28 to 35 and 36 to 42 d of age. Increasing air velocity to 180 m/min improved (P < or = 0.02) the growth rate of broilers from 43 to 49 d of age over birds receiving an air velocity of 120 m/min, but the incidence of mortality was not affected. These results provide evidence that increasing air velocity from 120 to 180 m/min is beneficial to broilers weighing 2.5 kg or greater when exposed to moderate temperatures.

Air Movements↗

PubMed2006

Effects of cysteamine on growth performance, digestive enzyme activities, and metabolic hormones in broilers.

A total of 600 avian male broilers at the age of 1 d were used to investigate the effects of cysteamine (CSH) on growth performance, digestive enzyme activities, and concentrations of serum hormones. The broilers received the same basal diets, with CSH added at 0 (control), 60, 90, 120, or 150 mg/kg. The feeding program consisted of a starter diet until 21 d and a grower diet until 42 d. The broilers with addition of CSH at 60 or 90 mg/kg had significantly higher growth rates during d 1 to 21 or d 21 to 42 compared with the control, respectively. However, adding 150 mg of CSH/kg significantly suppressed the growth of broilers. Adding 60 mg of CSH/kg significantly increased the activities of protease, amylase, and lipase in the pancreas and small intestinal contents during d 1 to 21, and the activities of protease and amylase in the small intestinal contents during d 21 to 42. Adding 90 mg of CSH/kg significantly increased the activities of lipase during d 1 to 21 and protease, amylase, and lipase during d 21 to 42 in small intestines. The activities of digestive enzymes during the whole period were suppressed by adding 150 mg of CSH/kg. The concentration of serum thyroxine was higher in the CSH-added birds during the whole period, whereas serum triiodothyronine was higher only during d 1 to 21 compared with the control. These findings indicate that low doses of dietary CSH may improve the growth performance and the activities of the digestive enzyme, but high doses of CSH appear to be detrimental to growth and digestion.

Aging↗