EFFECTS OF ENZYME AND FEEDING SYSTEM ON TURKEY PERFORMANCE

1Instituto de Investigación de Zonas Desérticas. Universidad Autónoma de San Luis Potosí. S.L.P. 78377. México. 2Universidad Autónoma de Chihuahua. F.R. Almada. CP 31453. México. 3Tecnológico Agropecuario 35. Tlalpizáhuac, Edo. de México. CP 56560. México. 4Dirección de Educación Tecnológica Agropecuaria. Ciudad de México. CP 03900. México. 5Universidad del Mar Campus Puerto Escondido. Vía Sola de Vega, km 1.5. Puerto Escondido. Mixtepec, Oaxaca. CP 71980. México. SHORT NOTE


SUMMARY
The aim of the present study was to evaluate an enzyme preparation with protease, amylase, cellulase, beta-galactosidase and pentosanase activity on productive and carcass performance of turkeys under a confined or semi-confined system.Eight hundred White Diamond turkeys (nine weeks old, 5084 g body weight) were randomly assigned to a 2 x 2 factorial arrangement: factor system (confined and semi-confined) and enzyme (0 and 0.1% as DM of total diet) four treatments, 5 replicas per treatment.Weight gain (WG), live weight (LW), feed intake (FI), forage intake (FGI), and carcass yield (CY) were recorded weekly for eight weeks.Turkeys under semiconfined system had higher final body weight, total gain, average daily gain, hot and cold carcass weight as well as less feed conversion than those under confined system.Hot and cold dressing was similar in turkeys under both systems.Enzyme increased final body weight, total gain, average daily gain, hot and cold carcass weight as well as reduced feed conversion ratio in turkeys under semi-confined system.Feed intake, hot and cold carcass dressing was not affected by enzymes.
Enzyme preparation had a beneficial effect on growth and carcass performance of turkeys in a semi-confined system.

INTRODUCTION
The majority of the high value protein ingredients utilized in alimentary rations for birds are from vegetable origin, they contain a large quantity of anti-nutritional factors as tannins, phytate, lectins, etc. (North and Bell, 1993;Lesson and Summers, 1997).Furthermore the carbohydrate fraction of these ingredients (i.e.soybean meal) consists mainly of non-starch polysaccharides (NSP) which are resistant to the digestive enzymes of turkeys (Bach, 2001).Many studies have reported the beneficial use of enzymes preparation containing a mix of proteases, cellulose, xilanase, glucanase and phytase in the broiler feeding, as a result of the improved nutrient digestion and absorption; live weight, daily gain, and most of the performance traits are improved (Bedford and Morgan, 1996).The objective of the present study was to determine the effects of exogenous enzymes on productive and carcass parameters of finishing turkeys on confined or semi-confined systems.

MATERIALS AND METHODS
Eight hundred White Diamond turkeys (nine weeks old, 5084 g average body weight) were used.Treatments: confined without enzyme (T1), confined with enzyme 0.1% (T2), semi-confined without enzyme (T3); and semi-confined with enzyme 0.1% (T4).Distributed in 20 pens; 40 turkeys/pen, 5 replicas/treatment.Birds under confined and semi-confined had free access to diets based in corn and soybean meal (table I According to Alltech, this enzyme preparation has protease, amylase, cellulase, betagalactosidase and pentosanase activity.In a weekly basis for eight weeks, body weight and feed intake was recorded from each pen.Then, daily weight gain and feed conversion (feed:gain) were calculated.After the experiment was done poults were slaughtered in an authorized abattoir.Carcass characteristics were evaluated after 8 weeks of trial.Hot carcass weight was taken the same day of slaughter, then carcass was kept at 4°C, cold weight was recorded 24 hours after.Using those values, percentages of hot and cold carcass dressing were calculated.Data were analyzed using a Mixed Procedure of SAS (1999) within a factorial design (enzyme x feeding system).
Treatments were fixed in model and pen was considered as a random effect.Initial body weight was tested as a covariate but it was not included in the model (p>0.05).Data over time were analyzed using repeated measure of SAS (1999) to test time x treatment interaction.When the interaction of the main effects (system x enzyme) was significant (p<0.05),LSMEANS was carried out to identify to the different averages.
Differences were set at p<0.05.Table II.Daily overall growth performance of turkeys confined or semi-grazing and supplemented with a enzyme preparation a .

RESULTS
The DM intake was not affected by feeding system or enzyme addition.Turkeys under semi-confined system without or with enzyme had higher final body weight (p<0.001),total gain (p<0.001),average daily weight gain (p<0.001),hot and cold carcass weight (p<0.001) as well as less feed conversion ratio (p<0.001)than those under confined system (table II).Hot and cold dressing percentages were similar in turkeys under both systems.Enzyme addition in turkeys under confined or semi-confined system improved total gain (p<0.05),average daily weight gain (p<0.01),feed conversion ratio (p<0.05),hot and cold carcass weight (p<0.001 and p<0.05 respectively).There was an interaction of feeding system x enzyme (p>0.05)for growth performance traits.

DISCUSSION
In this experiment was observed that live weight and daily live weight were increased with the use of the enzyme, showing a better response in animals on semi-grazing system, than those without the enzyme.Santos et al. (2004) tested the effect of an enzyme on turkey fed wheat based diets, and found that the enzyme supplementation improved growth performance and energy utilization of turkeys.In regard of feed intake in our study there was more forage consumption in turkeys with the use of the enzyme; feed intake in confinement was similar with or without the enzyme.There were no differences in carcass yield in turkeys either on feeding system or enzyme addition.The semi-confined system had poorly response to the enzyme addition, maybe for the presence of bacterial cellulolitic flora in the cecal sacs, like wild turkeys that mainly graze to obtain their feed (Bedford and Morgan, 1996).In conclusion the enzyme preparation had a beneficial effect on growth and carcass performance of turkeys in a semi-confined system.

Table I .
) Ingredients and chemical composition of diets.(Composición química de los ingredientes de las dietas).