Effect of the Litter Material on Drinking Water Quality in Broiler Production

Considering the importance of drinking water and its effect on broiler performance, drinking water quality was studied using six different litter materials. The presence of coliform bacteria and Escherichia coli was investigated. The following litter materials were used in the trial: wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum), 50% sugarcane bagasse (Saccharum L.) + 50% wood shavings, 50% sugarcane bagasse (Saccharum L.) + 50% rice husks, and plain sugarcane bagasse (Saccharum L.). A number of 1620 Ross one-dayold chicks were reared in 54 pens measuring 4.5 m each, equipped with a bell drinker and a tube feeder. Water samples were collected in sterile tubes on days 28 and 42 of the rearing period, and submitted to the laboratory for analyses. Microbiological data were organized by classes expressed in a logarithm scale, where the lowest contamination corresponds to class 1 and the highest contamination to class 4. Results showed that total coliform contamination was higher on day 28 than in the end of the rearing period, and that E. coli presence was detected during both analyzed periods. The litter materials that presented lower degree of water contamination, predominantly class 1, were sugarcane bagasse and 50% of sugarcane bagasse and 50% of rice husks.


INTRODUCTION
Poultry production has grown in Brazil, and since 2007 an average of 10 million tons of chicken meat are annually produced per year, with approximately 70% sold in the domestic market and 30% as exports (UBA, 2008).Broiler production technology has improved during recent years, allowing production growth within the same built area (Proudfoot et al., 1979;Santos et al., 2000;Santos et al., 2005).
The aim of using good litter material in broiler production is to prevent the direct contact of the bird with the floor and to promote the absorption of the fecal moisture.The use of appropriate litter also helps maintaining thermal environment balanced as it may reduce fermentation heat production in the rearing environment (Oliveira & Carvalho, 2002).Several materials have been used as litter, such as wood shavings and rice husks, and other materials, such as paper, peanut hulls, and sand have been studied as alternatives to reduce the use of wood and help preventing lumbering (Hernandes et al., 2002;Santos et al., 2000).
Animals need to consume sufficient water to satisfy their requirements.However, more important than water quantity is water quality, as the hygienic and physical-chemical quality of drinking water plays a key role in ensuring efficient animal production (Amaral et al., 1999;Li, 2009).Water is involved in every aspect of poultry metabolism and plays an important role in body temperature regulation, food digestion, and body waste excretion (Valias & Silva, 2001).Safe and adequate water supply is essential for efficient poultry performance as the chick's body contains approximately 80% water at hatching.Previous studies have shown that pathogenic bacteria and excessive amounts of chemicals in water supplies can reduce animal production, impair fertility, and cause the bird mortality in extreme cases (Abbas et al., 2008;Li, 2009).Bacteria in drinking water may induce health problems, and consequent lack of welfare (Koelkebeck et al., 1999;Manning et al., 2007).Moreover, contaminants in drinking water can leave residues in animal products, i.e. meat, milk and eggs, which adversely affect product sales and may pose health risks to humans.In order to improve water quality a number of solutions, such as filtration, coagulation, solar radiation, chlorination, and acidification have been developed to improve farm water quality (Barton, 1996;Macari, 1996).
This study aimed at evaluating drinking water quality in bell drinkers used in broiler production as function of the litter material used in houses during the rearing period.

Broiler housing and management
This study was conducted in an experimental broiler house located in the School of Agricultural Sciences of the Federal University of Grande Dourados, Brazil.The house was 50 m long, 10 m wide, and 3 m high.A total of 1620 Ross ® broilers were distributed in 54 pens measuring 4.5 m 2 each, equipped with a bell drinker and a tube feeder.Side walls were covered with curtains and inside temperature was controlled by the use of fans and foggers.Chicks were brooded using 250W infrared lamps, one per pen.The lighting regime was 24 hours of light during the entire rearing period, using 40W lamps providing an average of 22 lx.
All birds were offered feed and water ad libitum during the entire experimental period.The feeding program included three phases: a starter diet (1 -21 days), a grower diet (22 -35 days), and a finisher diet (36 -45 days).Birds were vaccinated against Marek's disease at the hatchery and were vaccinated against Newcastle disease in the drinking water at 10 days of age.
Broilers performance was evaluated in a weekly (feed intake, weight gain, feed conversion ratio, mortality, body weight and carcass yield).

Litter material
The following litter materials were tested: wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum), 50% of sugarcane bagasse (Saccharum L.) + 50% wood shavings, 50% of sugarcane bagasse (Saccharum L.) + 50% rice husks, and only sugarcane bagasse (Saccharum L.).The sugarcane bagasse was obtained in the region of Dourados and Napier grass was bought in nearby farms.The grass was chopped in particles of approximately 2.0-3.0 cm and sun-dried to 15% final moisture.Wood shavings and rice husks were purchased from in companies that market those products.All tested materials were placed on the broiler house floor at a height of 10 -8 cm.

Microbiological data of drinking water
Bell drinkers were daily cleaned and disinfected, and the drinking water was replaced twice daily.The drinking water in all treatments derived from the same water source, and free chlorine was used during the entire experimental period at 6 to 8 ppm in combination with acidification to a pH value of 5.0 (Macari, 1996), resulting in 5 ppm residual chlorine in the drinkers.Two samples per pen were collected in sterile tubes on days 28 and 42.After collection, samples were placed in thermally-insulated boxes containing ice, and immediately submitted to the laboratory for analyses.Determination of total bacteria and Escherichia coli counts were performed according to the Silva et al. (1997).
Microbiological data were organized by classes (Table 1) expressed in logarithmic scale, according to current literature (Ahmad et al., 2009;Carter et al., 2010;Souza et al., 1992).The lowest contamination corresponds to class 1, while the highest contamination to class 4. Experimental design A completely randomized experimental design in a 6 x 2 factorial arrangement (six litter materials and two sexes), with five replicates per treatment was applied.Data were submitted to ANOVA using SAS (1998) software package, and means were compared using Tukey's test at 95% significance level.contamination.Contamination levels were higher on day 28, when a predominance of the higher contamination classes.
All water samples presented Escherichia coli values higher the international standards (Amaral et al., 2001;Bettega et al., 2006;Carter et al., 2010).This contamination may be due to the use of bell drinkers.Studying the water quality in different types of drinkers, Barros et al. (2001) andValias &Silva (2001) found that bell drinkers may reduce the biological quality of the water provided to broilers, posing a high risk of contamination (Amaral, 2004).
As the hygienic status of drinking water varies greatly among farms, methods and strategies to identify critical contamination points need to be identified and updated, and measured to control water-borne diseases at farm level need to be applied.

CONCLUSION
The type of litter material used during rearing slightly influenced the microbiological quality of the drinking water of broilers the beginning of the rearing period.

Table 1 -
Classes of the Most Probable Number (MPN) of microorganisms (in logarithmic scale) used for the classification of drinking water quality.