Using kaolin as a feeding protocol to control ammonia gas production from the litter in broiler chicken production

Ezenwosu C and Udeh F U

Department of Animal Science, University of Nigeria, Nsukka, Nigeria
celestine.ezenwosu@unn.edu.ng

Abstract

Six weeks of study was carried out to investigate the litter chemical characteristics, percentage nutrient digestibility and litter microbial count loads of broiler chickens fed varying levels of kaolin as feed additive was investigated. 108-day ‘Anak strain” broiler chickens in which at two weeks of age were allotted to 4 dietary treatments in a completely randomized experimental design with 3 replicates of 10 birds each. Dietary treatments include: kaolin-0g/kg feed, kaiolin-5g/kg feed, kaolin-10g/kg feed and kaolin-15g/kg feed. Results showed that treatment groups had lower (P<0.05) ammonia litter content value, higher (P<0.05) percentage nutrient digestibility and the lower microbial litter count values in comparison with the control group. Furthermore, litter ammonia and microbial counts values among the treatments decreased (P<0.05) as the level of kaolin in the feed increased, while percentage nutrient digestibility values among the treatments also increased as the level of kaolin increased in the diets. It was concluded that up to 15g kaolin/kg feed can be safely included in broiler diets for improved litter quality and eventual reduction of ammonia production from the litter.

Key words: ammonia gas, broiler chickens, broiler performance, kaolin, nutrient digestibility

Introduction

Poultry sector despite its contribution to global meat demand is still faced with some environmental challenges such as ammonia production and volatilization from the litter. Ammonia gas is a product of degradation of protein-rich substrates such as animal manure by microbes (Munk et al 2017; Mata-Alvarez et al 2014). Ammonia is a leading upsetting gas that emanates from poultry litter. Its production is normal part of poultry production, but it undermines the sustainable development of poultry industry when its production is in excess due to poor litter conditions. Ammonia gas causes environmental pollution and contribute to the global climate change via the formation of nitrous oxide in the atmosphere. Furthermore, ammonia (NH₃) has negative effect on human and animal health as well as the environment (Almuhanna et al 2011). Ammonia (NH₃) gas is known to irritate the mucous membranes and damage the respiratory tract of humans and animals (Ihrig et al 2006).

However, to control the production of ammonia gas from the litter during poultry production such as broilers, a feeding protocols that will not only increase feed conversion efficiency (feed digestibility), but will also improve litter quality by reducing some factors that are implicated in ammonia gas production such as moisture and pH is of paramount importance. One of such feeding protocols is the utilization of mineral clay such as kaolin as feed additive.

Kaolin is thin clay, usually white in color, formed by the weathering of aluminous minerals and it is classified as a phyllosilicate, due to its absorption capacity and absence of primary toxicity (Owen et al 2012). Dietary inclusion of clays such as kaolin can moderate the processes of digestion, nutrient absorption, promoting a longer retention time of digester and thus, improving performance of farm animals (Safaei et al. 2014). Including clays in feed may cause an increase in villus height which in turn increases the surface area of the gastrointestinal tract and thus, increasing nutrient digestibility (Subramaniam et al 2015). Due to the presence of electrical charges, kaolin has a binding capacity of about 86% to 97% of the number of mycotoxins present in the feed. This same property allows also it to bind to toxins and bacteria in the intestine and absorb water significantly in the excreta. Actually, in the gastrointestinal tract, clays have the capacity to absorb water in an amount many times greater than their weight, preventing it from remaining free in the excreta. It has been demonstrated by (Yalçin et al 2017) that by reducing the rate of digester passage and colloid formation, clay positively improves the consistency of chicken faeces. Safaei et al. (2014) concluded that using kaolin in broiler chicken diets caused decreased content of moisture, nitrogen and calcium in broiler litter as well as reducing environmental pollution. Seeing that the issue of ammonia gas production which still remain a veritable threat to poultry production must be solved before a meaningful progress will be recorded in poultry sector, this study is therefore designed to investigate the litter chemical characteristics and percentage nutrient digestibility of broiler chickens fed varying levels of kaolin as a feed additive.

Materials and methods

Ethical consideration

This experiment was conducted according to the provisions of the Ethical Committee (MUC271SOYE01) on the use of animals and humans for biomedical research of the University of Nigeria, Nsukka, Enugu, Nigeria.

Study site and duration

The study was carried out at the Poultry Unit of the Department of Animal Science, Teaching and Research Farm, University of Nigeria, Nsukka, Nigeria. Nsukka lies within longitude 6˚ 45′E and 7˚ E and latitude 7˚ 12.5 ′N and on the altitude 447m above sea level. The climate of the study area is typically tropical, with relative humidity ranging from 65 to 80% and mean daily temperature of 26.8 ˚C (Okonkwo and Akubuo, 2007). The study lasted for 6 weeks.

Source of kaolin and feed ingredients

Kaolin was used as a feed additive for the study. The kaolin was purchased from a trusted chemical dealer in Nsukka Urban and Enugu Nigeria. The kaolin which was in a powdered form was kept at room temperature as specified by the manufacturer. Other feed ingredients were purchased from Hon. Peace Ugwu’s food stuff shop, Orie Orba, Nsukka, Enugu Nigeria.

Experimental diet

Basal diets for starter, finisher diets and their proximate compositions are presented in Tables 1. The chemical (proximate) compositions of the experimental diets were analyzed according to the methods of Association of Official Agricultural Chemists (AOAC, 2012).

Experimental birds and management

Total of 108-day old Anak strain broiler birds were used for the study. In the first two week of life, the birds were brooded together before they were weighed and randomly placed in various replicates per treatments in completely randomized experimental design.

Treatment were as follows:

Kaolin-0g: kaolin kg^-1 feed

Kaolin-5g:5g kaolin kg^-1feed

Kaolin-10g:10g kaolin kg^-1 feed

Kaolin-15g:15g kaolin kg^-1 feed

Prior to the arrival of the birds from the hatchery, the brooding house was cleaned with soap and disinfected with strong disinfectant after which wood shavings were spread. The pen was pre-heated few hours before the arrival of the birds with charcoal pot. The pre-heating was to achieve a nice brooding environment that would enhance bird’s activities. Feeding troughs and drinkers were also procured, disinfected and strategically positioned. Clean drinking water and feed were made ready before the arrival of the birds. General flock prophylactic management and routine vaccination were administered as follows; day 1: Intra ocular (new castle disease vaccine), week 2: Gumboro disease vaccine, week 3: Lasota (New castle disease vaccine), week 4: Gumboro disease vaccine, week 5: fowl pox vaccine, week 6-8: Lasota vaccine was repeated because of its prevalence in the farm. A stress pack was administered to the birds via drinking water at 100 g/50 liters (according to manufacturer’s recommendation) to boost appetite and energy supply. Dietary treatments and clean water were provided ad libitum throughout the trial periods. The room temperature was monitored with the use of thermometer, and lighting was provided using a 200v watt bulb.

Collection of data

Nutrient digestibility

At the last week of the feeding trial, two birds of similar weights were selected from each replicate and moved to a clean and disinfected metabolic cages. A 3-day adaptation period was allowed before the four-day data collection period. Feed intake was measured and droppings were collected from each bird daily. The collected droppings were weighed, air-dried at room temperature before being ground for proximate analysis according to procedure of AOAC (2012). Apparent nutrient digestibility (%) of crude fibre, crude protein, crude fat, ash and dry matter was computed according to the following equation.

Nutrient digestibility = (nutrient in feed-nutrient in faeces/nutrient in feed) × 100

Litter chemical parameters

Moisture was determined using oven method

Ammonia determination

Ammonia was ascertained by precipitation with sodium tetra phenyl borate as it is sparingly

soluble in ammonium tetra phenyl borate.

pH determination

The pH of the sample was determined using 20% of the sample.

Statistical design and analysis

Data generated were subjected to the analysis of variance (ANOVA) in CRD using statistical package (SPSS, 2003) Windows version 8.0. Mean differences were separated using Duncan^’s New Multiple Range Test (Duncan, 1955) as outlined by Obi (2002).

The statistical model used to test the effects of treatments on apparent nutrient digestibility, litter chemical characteristics and microbial load counts parameters was

Xij=µ+T₁ +∑ij

Where, Xij = any observation or measurement taken

µ = population mean

T₁ = treatment effect

∑ij =experimental error

i= number of treatments

j=number of replicates

Results

Table 2, figure1, 2 and 3 shows the result of litter chemical characteristics of broiler chickens fed varying levels of kaolin as feed additive. From the results, ammonia, pH, moisture and ammonium nitrate values of litter among the treatments were significant (P<0.05). Litter ammonia value of Kaolin-0g and Kaolin-5g were the same (P>0.05), but higher than values of 3.00 and 1.99 recorded in Kaolin-10g and Kaolin-15g that were also the same (P>0.05). Liter pH values of Kaolin-10g and Kaolin-15g were the same (P>0.05), but significantly lower than the values of 10.33 and 10.67 recorded in Kaolin-5g and Kaolin-0g. Moisture and ammonium nitrate values among the treatments followed the same trend observed in pH values among the treatments.

Figure 1. Percentage litter ammonia content of broiler chickens fed varying levels of kaolin as feed additive	Figure 2. Litter pH of broiler chickens fed varying levels of kaolin as feed additive

Figure 3. Percentage litter moisture of broiler chickens fed varying levels of kaolin as feed additive

Table 3 shows the results of the apparent nutrient digestibility (%) of broiler chickens fed varying levels of kaolin as feed additive. Apparent nutrient digestibility values of crude fat, crude protein, crude fibre, ash and dry matter were significant (P<0.05). Crude fat apparent digestibility (%) value of Kaolin-15g, Kaolin-10g and Kaolin-5g were the same (P>0.05), but significantly higher than value of 93.33 recorded in Kaolin-0g. Apparent crude fibre digestibility of Kaolin-0g and Kaolin-5g were the same (P>0.05), but significantly lower than the values of 62.67 and 68.33 recorded in Kaolin-10g and Kaolin-15g. Ash apparent digestibility % values of kaolin-10g and kaolin-15g were the same (P>0.05) and the highest, followed by Kaolin-5g and Kaolin-0g. respectively. Crude protein apparent digestibility % value of Kaolin-10g and Kaolin-15g were the same (P>0.05), but lower than values of 77.67 and 77.33 recorded in Kaolin-5g and Kaolin-0g that were also the same statistically. Dry matter apparent digestibility % of Kaolin-15g was the highest among the treatment, followed by both Kaolin-10g, Kaolin-5g and Kaolin-0g that were the same also(P>0.05).

Discussions

Table 2, figure1, 2 and 3 shows the result of litter chemical characteristics of broiler chickens fed varying levels of kaolin as feed additive. From the results, Kaolin-0g recorded higher ammonia and ammonium nitrate litter values compared to treatment groups (Kaolin-5g, Kaolin-10g and Kaolin-15g). This could be linked to higher moisture and pH value (Table 2, figure 1, 2 and 3) recorded in kaolin-0g compared to treatment groups. Generally, moisture is one of the main factors that is implicated in ammonia (NH₃) production from poultry litter (Elliott and Collins, 1982). High moisture and pH of litter encourages the degradation of nitrogen carrying organic matters in the litter to ammonia. Ammonia production tends to increase as litter pH increases and decreases as litter pH decreases. Reece et al (1979) reported that ammonia volatilization can be decreased when the litter pH falls below 7 and deeply enhanced when pH of litter is above 8. Degradation of uric acid to ammonia is mainly enhanced under alkaline litter state (Rappet and Muller, 2005). Effect of enzyme called uricase which catalyzes the degradation of uric acid to ammonia gets to utmost at pH of 9 and thus increasing ammonia production from the litter. Safaeikatoul et al (2011) further explained that low litter pH has an important role in decreasing ammonia production in the litter. According to Shah et al (2007) part of ammonium nitrate (NH₄⁺) during litter microbial degradation may be converted into ammonia when the pH, temperature and litter moisture are high.

On the other hand, the reduced ammonia and ammonium nitrate values recorded in Kaolin-5g Kaolin-10g and Kaolin-15g could be considered as the result of the reduced moisture and pH caused by the inclusion of kaolin in the diets. This agrees with the work of Safaei et al (2014) who used kaolin in broiler chicken diets and observed decreased content of moisture in broiler litter as well as reduction in environmental pollution. Similar results to the present study were recorded by Nikolakakis et al (2013) who after including different levels of clay (zeolite) in the diets of broiler chickens observed lower moisture in the litter. Also, reduced litter pH recorded in this present study in favor of the treatments groups was similar to the findings of  Safaeikatoul et al (2011) who used sodium bentonite as feed additive in broiler diet and observed that litter pH on the 14th day of the trial was significantly (p<0.05) decreased compared the control group. Actually, in the gastrointestinal tract, clays such as kaolin have the capacity to absorb water in an amount many times greater than their weight and thus, preventing it from remaining free in the excreta. It has been demonstrated by (Yalçin et al 2017) that by reducing the rate of digester passage and colloid formation, clay can positively improve the consistency of chicken faeces. It has also been shown that clays help tin reducing the volume of harmful gastrointestinal gases, off-site transport of odors, and other broiler facility pollutants (Amova et al 2011). Furthermore, Parizadian et al (2013) also observed a significant reduction in moisture content of excreta and improved quality of litter after inclusion of clay (clinoptilolite) in the broiler chicken’s diet. These authors stated that broiler’s litter when moist is a propitious environment for the growth of bacteria and fungi; and also, the main cause of ammonia emissions from the litter which, serious environmental factors that affect the production of broiler chickens. Castaing (1989) and Olver (1997) observed that the use of clay may cause reduction of litter moisture in broilers production and laying hens’ due the capacity of this substance to absorb and retain ammonia (Castaing 1989; Olver 1997). Good litter qualities observed in this present study is also in agreement with Valladares et al (2014) who evaluated the effects of different kaolin levels in the feed of broilers and observed better quality of litter.

Results of apparent nutrient digestibility (%) of broiler chickens fed varying levels of kaolin as feed additive is shown in Table 3. Apparent nutrient digestibility (%) increased as the level of kaolin in the diet increased. The improvement in nutrient digestibility recorded in this present study could be attributed to better health status of the GIT or larger villi surface area which improved nutrient digestion and absorption (Mansoub, 2011). Inclusion of clays such as kaolin in feed causes an increase in villus height, which in turn increases the surface area of the gastrointestinal tract and thus, increasing nutrient digestibility (subramaniam et al 2015). Castaing (1989) reported that kaolin brings about improvement in nutrients digestibility by reducing the digester transit time. Furthermore, kaolin as a Clay can improve intestinal integrity through excretion of toxins produced by pathogenic microorganisms present in the gastrointestinal tract (Xu et al 2003). It is also documented in the literature that dietary inclusion of clays such as kaolin can moderate the processes of digestion, nutrient absorption, promoting a longer retention time of digester and thus, improving performance of farm animals (Safaei et al 2014). It may be reliable also to assert that the reduced ammonia values recorded in favor of the treatment groups could also be traceable to the percentage increase in nutrient digestibility. When feed consumed by birds is well digested, absorbed and utilized, it will lead to reduced feacal output and thereby reducing the amounts nutrients in the litter that can be converted to ammonia by microbes in the litter. Ammonia becomes volatile after microbial decomposition of nitrogen compounds present in the waste; particularly uric acid excreted naturally by birds. The lower the nitrogen present in excreta because of its increased digestibility, the lower the concentration of volatile ammonia in the aviaries (Schneider 2017).

References

Almuhanna E A, Ahmed AS, Al-yousif Y M 2011 Effect of air contaminants on poultry immunological and production performance.

Association of Official Analytical Chemists AOAC 2012 Official Methods of Analysis of AOAC International, 19th Edition. Association of Official Analytical Chemists International, Gaithersburg, Maryland, USA.

Castaing J (1989 Effet de l'inclusion de 2% de Sepiolite "Exal" clans les aliments á deux niveaux enérgetiques présentés en granulés pour porcelets et porcs charcuters. Journés de la Recherche Porcine em France, v.21, p.51-58. Available from: <http://www.journees-recherche porcine.com/texte/index. htm.

Harrigan W F and McCance M E 1976 Laboratory Methods in Food and Dairy Microbiology. Academic Press Incorporated, London.

Ihrig A, Hoffman J and G Triebig 2006. Examination of the influence of personal traits and habituation on the reporting of complaints at experimental exposure to ammonia. International Archives of Occupational Environmental Health 79: 332-338.

Mansoub N H 2011 Comparison of effects of using Nettle (Utrica dioica) and probiotic on performance and serum composition of broiler chickens. Glob. Vet. 6, 247-250.

Mata-Alvarez J, Dosta J, Romero-Güiza M S, Fonoll X, Peces M, Astals S 2014 A critical review on anaerobic co-digestion achievements between 2010 and 2013. Renew Sustain Energy Rev 36:412–427.

Munk B, Guebitz G M, Lebuhn M 2017 Influence of nitrogen-rich substrates on biogas production and on the methanogenic community under mesophilic and thermophilic conditions. Anaerobe 46, 146e154. https://doi.org/10.1016/ j. anaerobe.2017.02.015.

Nikolakakis I, Dotas V, Kargopoulos A, Hatzizisis L, Dotas D and Ampas Z 2013 "Effect of natural zeolite (clinoptilolite) on the performance and litter quality of broiler chickens," Turkish Journal of Veterinary & Animal Sciences: Vol. 37: No. 6, Article 12. https://doi.org/10.3906/vet-1212-9 Available at: https://journals.tubitak.gov.tr/veterinary/vol37/iss6/12.

Obi I U 2002 Statistical methods of detecting differences between treatments means and research methodology issues in laboratory and field experiments.2 ^nd Ed.Express Pub.Ltd.Enug u.Pp13-21.

Owen O J, Nodu M B, Dike U A, Ideozu H M 2012 additives on the growth performance of broiler chickens. G J of Agric Sci.

Olver M D 1997 Effect of feeding clinoptilolite (zeolite) on the performance of three strains of laying hens. British Poultry Science, v.38, p.220-222.

Rappert S, Müller R 2005 Odor compounds in waste gas emissions from agricultural operations and food industries. Waste Manag. 2005; 25:887–907.doi: 10.1016/j.wasman.07.008.

Reece F N, Bates BJ and Lott B D 1979 Ammonia control in broiler houses. Poult. Sci., 58: 754-760.

Safaeikatouli M, Jafariahangari Y, Baharlouei A and Shahi G 2011 The Efficacy of Dietary Inclusion of Sodium Bentonite on Litter Characteristics and Some Blood Hormones in Broiler Chickens. Journal of Biological Sciences, 11: 216-220.

Schneider A F, Y M, Almeida D S, Roeder J VC, Xavier J S, Gewehr C E 2017 Natural Zeolites in broiler diet. 69:191-197. https: 10.1590/1678-8717

SPSS 2003 Statistical Package for social Sciences. Window Version 8.0.

Safaei M, Jafariahangari Y, Mutalib M S A and Rezaei R 2014 Asian journal of animal and veterinary advances. Vol 9: 64-71.

Subramaniam M, Kim I H 2015 Clays as dietary supplements for swine: A review. J. Anim. Sci. Biotech, 6, 2–9.

Xu Z R, Hu CH, Xia M S, Zhan X A and Wang MQ 2003 Effects of dietary fructooligosaccharide on digestive enzyme activities, intestinal microflora and morphology of male broilers. Poultry Science, 82: 1030-1036. https://doi.org/10.1093/ps/82.6.1030.

Vallodares M, Fillo CAS, Lemo M J, Nak S Y, Dias T F V, Alves O S, Souza D S, Calixto SY 2014 Proceedings of the 10^th: XXVI Congress.

Yalçın S, Yalçın S, Gebeş E S, Şahin A, Duyum HM, Escribano F, Ceylan A 2017 Sepiolite as a feed supplement for broilers. Applied Clay Science, 148: 95-102.

Shah S B, Baird C L and Rice J M 2007 Effect of a metabolic stimulant in ammonia volatilization from broiler litter. J.Apllied Poult.Res.,16:240-247.