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Three experiments were conducted to study the effects of crude enzyme preparations on the performance and gastrointestinal tract size of chicks fed wheat and barley diets. In the first experiment, enzyme addition (100 and 200 mg/kg of Roxazyme G and 1,000 mg/kg of Avizyme SX) to diets containing Bedford barley improved weight gain (6%) and the feed to gain ratio (5%) over a 6-wk period for both male and female broilers. In Experiment 2, enzyme addition to diets containing Scout (hulless) and Bedford (hulled) barley improved (P < or = .05) weight gains of Leghorn chicks by 25 and 11% and the feed to gain ratios by 10 and 6%, respectively. Feed consumption increased significantly (16%) only in the case of birds fed enzyme with Scout barley. Corresponding reductions in the relative weights of the crop and gizzards were 15 and 17% for birds fed Scout barley and 7 and 8% for those fed Bedford barley. Enzyme treatment of the diet containing Scout barley also reduced the relative length of the duodenum, jejunum, and ileum and the relative weight of the proventriculus, whereas a similar treatment of Bedford barley resulted in changes in the relative length of the duodenum and jejunum (P < .05). In the final broiler experiment (42 days), crude enzyme addition (100 mg/kg) to wheat and barley diets improved weight gains by 13 and 9% and feed to gain ratios by 7 and 10%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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Concerns regarding the welfare of laying hens raised in battery cages have led to the development of enriched cages that allow hens to perform natural behaviors including nesting, roosting, and scratching. This study was conducted to compare indices of production and welfare in birds housed in 2 different caging systems. Shaver White hens were housed from 21 to 61 wk in either conventional battery cages (n = 500; 10 cages; 5 hens/cage; floor space = 561.9 cm(2)/hen) or enriched cages (n = 480; 2 cages; 24 hens/cage; floor space = 642.6 cm(2)/hen) and were replicated 10 times. Enriched cages provided hens with a curtained nesting area, scratch pad, and perches. Production parameters and egg quality measures were recorded throughout the experiment. Plumage condition was evaluated at 37 and 61 wk. Bone quality traits and immunological response parameters were measured at 61 wk, and 59 and 61 wk, respectively. Hen-day egg production, feed consumption, egg weight, and percentage of cumulative mortality of laying hens were not affected by the cage designs. Specific gravity and the percentage of cracked and soft-shelled eggs were also similar between the 2 housing systems. The incidence of dirty eggs was, however, significantly higher (P < 0.0001) in enriched cages than in conventional cages. Feather scores were similar between birds except for the wing region, which was higher (P < 0.05) for hens housed in conventional cages. Bone quality measures tended to be higher for hens housed in enriched cages compared with hens in conventional cages. However, the increase was significant only for bone mineral density. Immunological response parameters did not reveal statistically significant differences. Overall, laying performance, exterior egg quality measures, plumage condition, and immunological response parameters appear to be similar for hens housed in the 2 cage systems tested. Enrichment of laying hen cages resulted in better bone quality, which could have resulted from increased activity.

No abstract

In light of evidence supporting a need for humans to increase their dietary folate intakes, experiments were conducted to evaluate the extent to which egg folate levels could be increased. In Study 1, Hyline W36 hens (n = 6/diet) received a barley-based diet, containing 0 or 10 mg/kg of crystalline folic acid, to establish the potential for folate incorporation into table eggs. In Study 2, 70 hens were divided into seven treatment groups (n = 10 hens/diet) and received diets supplemented with 0, 1, 2, 4, 8, 16, or 32 mg folic acid/kg diet. In Study 3, 64 hens received the barley-based diet with or without 4 mg folic acid/kg diet. Eggs were collected and stored for 0, 7, 14, 21, or 28 d, prior to folate determinations. The folate content of eggs was determined by HPLC for 5-methyltetrahydrofolate (the sole form of folate in egg yolk). Results from Study 1 showed that a 10 mg/kg inclusion of folic acid increased folate incorporation into egg yolk (41.0 +/- 0.7 microg /egg) over that of an unsupplemented diet (17.5 +/- 0.7 microg /egg; P = 0.0001). In Study 2, the response of egg folate to dietary folic acid supplementation was saturable, with 90% of maximal egg folate levels established at approximately 4 mg folic acid/ kg diet. Results from Study 3 showed that folate levels are stable, in control and fortified eggs, during 28 d of storage at 4 C. In terms of its nutritional value, one large egg collected from a folic acid-supplemented hen provided approximately 12.5% of the recommended dietary allowance (RDA) for adult humans (RDA = 400 mg/d).

Enrichment of eggs with folate is possible when dietary folic acid levels are increased. However, development of optimal strategies for the production of folate-enriched eggs requires knowledge as to differences due to strain of bird and a greater understanding of the factors limiting egg folate deposition. To this end, a study was designed to determine the response of two leghorn strains that differ in production performance. Hyline W36 and W98 hens (n = 6 per diet) received a barley-based ration containing 0, 2, 4, 8, 16, 32, 64, or 128 mg/kg of crystalline folic acid for 21 d. Response criteria included production parameters, measures of blood folate status, and egg folate content. Significant (P < 0.05) main effects of folate supplementation were observed for egg folate content and plasma folate, which increased, and homocysteine concentrations, which decreased with supplementation; performance, however, was not affected. The Hyline W98 strain had significantly (P < 0.05) higher total egg and yolk weights and feed consumption when compared with the W36. Significant (P < 0.05) ration x strain interactions were observed for egg and yolk weight, egg folate content, and plasma homocysteine. The higher egg mass producing strain, Hyline W98, benefited from increased folic acid through a reduction in plasma homocysteine concentrations, suggesting that this strain has a higher requirement for folate than the W36 strain. Overall, egg folate content is maximized when crystalline folic acid is supplemented to the diet at 2 mg/kg or higher. Higher levels of egg folate are not achieved due to the saturation of the precursor pool for egg folate deposition.

Three experiments were conducted to evaluate the effect of supplementing phytase and xylanase on nutrient digestibility and performance of growing pigs fed wheat-based diets. In Exp. 1, 10 diets were fed to 60 pigs from 20 to 60 kg of BW to determine the effect of combining phytase and xylanase on apparent total tract digestibility (ATTD) of nutrients and growth performance. The 10 diets included a positive control diet (PC; 0.23% available P; 0.60% Ca) and a negative control diet (NC; 0.16% available P; 0.50% Ca) supplemented with phytase at 0, 250, and 500 fytase units (FTU)/kg and xylanase at 0, 2,000, and 4,000 xylanase units (XU)/kg in a 3 x 3 factorial arrangement. In Exp. 2, 6 ileally cannulated barrows (initial BW = 35.1 kg) were fed 4 wheat-based diets in a 4 x 4 Latin square design, with 2 added columns to determine the effect of combining phytase and xylanase on apparent ileal digestibility (AID) of nutrients. The 4 diets were NC (same as that used in Exp. 1) or NC supplemented with phytase at 500 FTU/kg, xylanase at 4,000 XU/kg, or phytase at 500 FTU/kg plus xylanase at 4,000 XU/kg. In Exp. 3, 36 barrows (initial BW = 55.5 kg) were fed 4 diets based on prepelleted (at 80 degrees C) and crumpled wheat for 2 wk to determine the effect of phytase supplementation on ATTD of nutrients. The 4 diets fed were a PC (0.22% available P; 0.54% Ca) and a NC (0.13% available P; 0.43% Ca) alone or with phytase at 500 or 1,000 FTU/kg. All diets in the 3 experiments contained Cr(2)O(3) as an indigestible marker. No synergistic interactions were detected between phytase and xylanase on any of the response criteria measured in Exp. 1 or 2. There were no dietary effects on growth performance in Exp. 1. In Exp. 1, phytase at 250 FTU/kg increased the ATTD of P and Ca by 51 and 11% at 20 kg of BW or by 54 and 10% at 60 kg of BW, respectively, but increasing the level of phytase to 500 FTU/kg only increased (P < 0.05) ATTD of P at 20 kg of BW. In Exp. 2, phytase at 500 FTU/kg increased (P < 0.05) the AID of P and Ca by 21 and 12%, respectively. In Exp. 3, phytase at 500 FTU/kg improved (P < 0.05) ATTD of P by 36%, but had no further effect at 1,000 FTU/kg. Xylanase at 4,000 XU/kg improved (P < 0.05) AID of Lys, Leu, Phe, Thr, Gly, and Ser in Exp. 2. In conclusion, phytase and xylanase improved P and AA digestibilities, respectively, but no interaction between the 2 enzymes was noted.