The effect of litter materials on broiler performance: a systematic review and meta-analysis.

1. Divergence in outcomes from studies on the effects of litter materials on body weight, feed intake, feed conversion and mortality in broilers has led to a need for a meta-analysis to quantify their effects.2. A systematic search of published quantitative research relating to wood shavings and alternative bedding litters was conducted using databases.3. Means, standard deviations and sample sizes were extracted from each study. The response variables were analysed using the standardised mean difference (SMD, control treatment minus alternative litters).4. The literature demonstrated that alternative materials have no impact on feed intake in broilers, compared to wood shavings (SMD = 0.064, 95% CI = -0.101-0.229, P = 0.44).5. There was a positive overall effect of wood shavings on body weight (SMD = 0.253, 95% CI = 0.073-0.433, P = 0.006), feed conversion (SMD = -0.169, 95% CI = -0.327 - -0.012, P = 0.03) and mortality (SMD = -1.069, 95% CI = -1.983 - -0.155, P = 0.02) of broilers, compared to other litter types.6. Subgroup meta-analysis revealed that straw, when used as an alternative litter material to wood shavings, may be responsible for lower body weight (SMD = 0.654, 95% CI = 0.162-1.146, P = 0.009), worse feed conversion (SMD = -0.487, 95% CI = -0.828 - -0.145, P = 0.005) and higher mortality rates of broilers (SMD = -3.25, 95% CI = -5.681 - -0.819, P = 0.009). Rice husks impaired body weight compared to wood shavings (SMD = 0.535, 95% CI = 0.065-1.004, P = 0.02).7. It was concluded that different litter types do not affect the broilers' feed intake. Conversely, broilers kept on straw showed lower body weights, worse feed conversion and higher mortality rates, in comparison to wood shavings. Rice husks decreased body weight compared to wood shavings.

Phytotoxicity as an indicator of stability of broiler production residues.

Beddings used for successive broiler lots act as substrate to absorb water and feed from the excreta and may be subsequently used as agricultural fertilizers. This study evaluated the physicochemical characteristics and the phytotoxicity of beddings used to raise five consecutive broiler lots in five aviaries. Samples were collected for beddings not used yet and for beddings used at each of the five broiler lots. Lettuce and cucumber seeds were considered as phytotoxicity bioindicators. As beddings were used for greater number of lots, N, Ca, K, Mg and P contents generally increased, but the C content decreased, the pH alkalinized and humidity was reduced (P < 0.05). The germination index for lettuce and cucumber seeds was reduced with increased bedding (P < 0.05). Beddings used for at least five broiler lots presented decreased C:N ratio and would not recommended for agricultural use due to its toxicity for both tested seeds.

An assessment of the effectiveness of four in-house treatments to reduce the bacterial levels in poultry litter.

Although the use of quicklime (CaO) and tarping are common handling practices aimed at the reuse of litter in the Brazilian poultry industry, few scientific studies have proven the effectiveness of these methods in reducing the pathogenic microbial load during fallowing. The objective of this study was to evaluate the following litter treatments: T1 no treatment (control), T2 quicklime (300 g m(-2)), T3 tarping, T4 tarping+quicklime (300 g m(-2)). The litter samples were collected on day zero and on the sixth and twelfth days after the start of fallowing. The use of quicklime alone or quicklime+tarping was more effective (P<0.05) in reducing bacteria when compared to litter tarping. Except for the control group, all treatments resulted in a more than 84% reduction in the count of colony-forming units (CFUs) at the end of fallowing. It is concluded that the use of quicklime alone in practical terms is the most indicated treatment for the reduction of the bacterial load of poultry litter.

Quicklime treatment and stirring of different poultry litter substrates for reducing pathogenic bacteria counts.

Testing different management practices can help to identify conditions that decrease or even eliminate pathogenic bacteria in poultry litter. A trial was conducted to evaluate the effects of daily manual stirring (rotation of the litter with a pitchfork) for the first 14 d of a bird's life (WDR), in 3 types of poultry litter substrates and quicklime treatment (CaO) during layout time between flocks on pathogenic bacteria occurrence (cfu). A total of 216 male Cobb broilers were randomly allotted to 18 pens with new litter (experimental unit). A split-plot design, with 6 treatments allotted to the main plots, was used: 1) wood shavings (WS) + WDR, 2) WS without stirring up to 14 d (WODR), 3) rice hulls (RIH) + WDR, 4) RIH + WODR, 5) mixture of 50% RIH and WS + WDR, and 6) mixture of 50% RIH and WS + WODR. Two treatments were allotted to the subplots: 0 and 300 g of CaO•m(-2) litter. After depopulation, litter samples were collected, and CaO was incorporated into the litter in the designated half of each pen. The cfu from litter samples after 7 d of the quicklime treatment were counted on Chapman agar, brain heart infusion media, and MacConkey agar. The data were analyzed using ANOVA, and the means were compared by least squares means (P < 0.05). Neither the type of substrate nor the act of stirring affected the cfu. The incorporation of 300 g of CaO•m(-2) litter efficiently reduced the cfu observed on brain heart infusion, Chapman agar, and MacConkey agar media by 57.2, 66.9, and 92.1%, respectively, compared with control (6.4, 17.9, and 46.1%; P < 0.001). In conclusion, the incorporation of 300 g/m(-2) of quicklime in poultry litter reduces the cfu, regardless of the substrate and stirring performed.

Research on Salmonella in broiler litter reused for up to 14 consecutive flocks.

The reuse of poultry litter is a common practice in the Brazilian poultry industry for flocks of healthy chickens, due to 2 fundamental aspects: production cost and environmental sustainability. Litter is a potentially important source of infection for Salmonella, which requires characterization by microbiological analysis in different aspects of management and reuse. The objective of this study was to verify the occurrence of Salmonella in broiler litters reused up to 14 times in Brazilian poultry farms. From January 2008 to November 2010, 8,877 samples of litter on disposable shoe covers were analyzed from broiler farms located in southern Brazil. At the laboratory, samples were processed for isolation and identification of Salmonella. Of the total 8,877 samples analyzed, only 2.5, 5.27, and 2.08% were positive for Salmonella in the years 2008, 2009, and 2010, respectively. Linear regression models indicate that there is a significant decrease (P < 0.05) in the count of samples positive for Salmonella with the reuse of litter. After the sixth reuse of the litter, values of samples positive for Salmonella are significantly (P < 0.0001) lower than expected (chi-squared test). Results show that the reuse of treated broiler litter is a safe practice and contrary to expectations, it substantially decreases the bacterial load of Salmonella.