Novel feeding protocol for control of ammonia gas and odour production from broiler birds’ litters to foster environmental friendliness

Udeh F U, Onodugo M O, Okoye P E, Kalu J C, Arum E C, Ugwuozor J C and Udeh V C

Department of Animal Science, University of Nigeria, Nsukka
matthew.onodugo@unn.edu.ng

Abstract

Substances derived from herbs and clay materials are natural, less toxic and ideal to serve as feed additives for poultry litter amendment. This study was conducted to determine the effects of Rosemary Leaf Meal (RLM) and Sodium Bentonite (SB) on Litter Characteristics of broiler birds. A total of 180 day-old chicks of Cobb 500 strain of broilers were used for the study. The birds were randomly grouped and allocated to six (6) dietary treatments, which contained, (0g RLM and 0g SB) and served as Control,  (0g RLM and 15g SB),  (3g RLM and 0g SB),  (3g RLM and 15g SB),  (6g RLM and 0g SB) and  (6g RLM and 15g SB), respectively, per kilogramme of feed, with 30 birds per treatment. Each treatment was replicated 3 times with 10 birds per replicate in a 2*3 factorial arrangement in a completely randomized design (CRD). The experiment lasted for 8 weeks. At weeks 4 and 8 of the experimental period, litter samples were collected and analyzed according to treatments, to determine the pH, moisture and ammonia contents. The results of the litter characteristics showed that there were significant (p<0.05) decrease in pH level, from (6.45 to 4.92), whereas there were no significant (p>0.05) difference in moisture and ammonia content, at week 4 of the study. At 8 weeks of the study, there were significant (p<0.05) decrease in pH level (7.75 to 7.07) and in ammonia gas content (11.8 to 9.62). The interaction effect of RLM and SB on litter characteristics at 8weeks of the experiment showed significant (p<0.05) decrease in ammonia (12.37 to 8.13ppm), pH level (7.80 to 6.23) and moisture content (16.47 to 13.73) in T4. It was concluded that, 15g SB and 3g RLM per kg feed improved litter characteristics by reducing ammonia gas production and odour in the litter and thus, recommended that 15g SB and 3g RLM should be used by farmers to improve litter characteristics in order to reduce ammonia gas production and control odour in poultry houses, hence, maintain friendly environment.

Keywords: ammonia gas, broilers, environment, litter, novel feeding, odour control

Introduction

Poultry industry has played significant role in the contribution to the global meat demand, but, the sector is still battling to overcome environmental challenges emanating from ammonia gas, odour and volatilization from the litter (Ezenwosu and Udeh 2022). It has been documented in the literature (Mata-Alvarez et al 2014), that when protein-rich substances such as poultry litters are degraded by microorganisms, ammonia gas is produced and emitted into the environment (Munk et al 2017). Ammonia gas (NH₃) causes environmental pollution and contribute to the global climate change and global warming through the formation of nitrous oxide (N₂O) in the atmosphere and creating a vicious circle (Brind’Amour and Lee, 2022). Evidences of the negative impact of ammonia gas (NH₃) on human, animal, plant health and, as well as, the environment are numerous in the literatures (Krupa, 2003; Ihrig et al 2006; Almuhanna et al 2011; Guthrie et al 2018). Considering these challenges, it is pertinent to develop a novel feeding protocol that will proffer lasting solution to ammonia gas production, without increasing cost of production, while, maintaining quality output and products in poultry (broiler) production.

Rosemary is an aromatic plant and one of the most commonly used medicinal plants in folk recipes. It is used as a spice and flavoring agent in food processing. The main components of rosemary are carnosol, carnosic acid and caffeic acid (Nieto et al 2018). Rosemary is important for fighting bacterial infections and reducing heat stress because of its antioxidant nutrient (Begum, 2013). Rosemary is a plant extract that displays many characteristics, but above all it is an easy route for the utilization of animal nutrients (Ghazalah et al 2008). Rosemary works as a detoxifier, pain reliever and respiratory support for birds. In other words, Rosemary is seen as an ideal supplement whose primary importance is to preserve egg quality, especially in laying birds, helps reduce heat stress, regulate microbial loads in the gut of birds and also, helps to maintain a careful level of digestibility in broilers (Zhang et al 2023).

Sodium Bentonite are clays with strong colloidal properties that absorbs water quickly, which means they swell and multiply in volume creating a gelatinous substance (Atman, 2020). Studies have shown over the years that poultry birds are always in contact with their litter and sodium bentonite has been used as a litter treatment (Safaeikatouli et al 2011). The amount of Sodium Bentonite used in animal production is not expected to have a negative impact on the environment (Guido et al 2017). Wet litter and foul odour in poultry farms are growing problems worldwide. Thus, maintaining quality litter characteristics is very important, to improve bird's health and welfare and minimize odour emissions. Increased mineral excretion by birds can reduce litter characteristics (van der Hoeven-Hangoor,. 2014). Therefore, Sodium Bentonite has the potential to improve bedding quality by enhancing mineral and protein bio-availability. Fecal/ bedding quality is usually measured by water activity, humidity and free water content (van der Hoeven-Hangoor, 2014). The amount of water in litter determines microbial activity (Wadud et al 2012) and ammonia production (Miles et al 2011), which were known to affect litter. Therefore, it is important to study the effects of rosemary leaf meal and sodium bentonite on litter characteristics, ammonia gas and odour release in broiler production, as there are not enough existing studies comparing the effect of Rosemary and Sodium Bentonite on litter characteristics, ammonia gas production and odour control in broiler production house and thus optimal dietary concentration requirements of birds needs to be established. The aim of the study was to employ novel feeding protocol on control of ammonia gas production and odour from Broiler birds litter to foster environmental friendliness.

Materials and methods

Location of the study

The experiment was carried out at the Poultry Unit of the Department of Animal Science Teaching and Research Farm, University of Nigeria, Nsukka. Nsukka is situated within the equatorial rainforest belt of the tropics and falls specifically within the savanna vegetation zone. Nsukka town lies on latitude 70 24 north and longitude 60 24 east and has an annual rainfall ranging from 986mm to 2,098mm. The town is situated at an altitude of 430m above sea level with humid tropical climate (Ndofor-Foleng et al 2015). The Experiment lasted for a period of 8 weeks.

Experimental materials

Commercial dried Rosemary Salvia rosmarinus was sourced from Ogige Market in Nsukka, which were ground to powered form. Sodium Bentonite was sourced from Geo-chem Ventures (home for) Chemicals and Scientific Instruments.

Experimental treatment

1=0g of Sodium Bentonite and 0g of Rosemary per/kg of feed

2=0g of Sodium Bentonite and 3g of Rosemary per/kg of feed

3=0g of Sodium Bentonite and 6g of Rosemary per/kg of feed

4=15g of Sodium Bentonite and 0g of Rosemary per/kg of feed

5=15g of Sodium Bentonite and 3g of Rosemary per/kg of feed

6=15g of Sodium Bentonite and 6g of Rosemary per/kg of feed

Experimental animals and management

A total of 180 day-old broiler chicks of Cobb 500 strain were used for the experiment. The chicks were randomly assigned to six (6) treatment group. Each treatment contained 30 birds and was replicated (3) times. Each replicate was assigned 10 birds in a 2×3 factorial arrangement in completely randomized design (CRD). The birds were managed in deep litter system. Prior to the arrival of the day-old chicks, the pens were thoroughly washed, dried and covered with dry wood shavings as the litter materials. The pens were equipped with feeders and drinkers and preheated with solar system heater to a temperature of 37^oC. On arrival, the chicks were weighed individually using an Electronic digital weighing scale. Feed and water were provided ad libitum . Vaccination and medications were employed as at when due.

Experimental diet

The birds were fed commercial broiler starter and finisher diets fortified with the test ingredient. Proximate Analysis was carried out according to the procedure described by A.O.A.C (1990) and it is presented in Table 1.

Laboratory procedures for determination of ammonia, pH and moisture content of the litter

Ammonia and pH were determined according to the procedures described by Ivančič and Degobbis, (1984), whereas moisture content was determined according to the procedure described by A.O.A.C (1990).

Litter sample collection

Litter samples were collected from 6 random sites in each treatment. Those samples were taken from the center of the pen, mid-way between the centre, under the feeder, the four corners of the pen. Litter samples (100g) were collected with the aid of hand gloves to avoid cross contamination. Samples were put in separate plastic bags, sealed and immediately stored in the refrigerator (for one day) for analysis. Samples obtained were subjected to laboratory analysis to determine moisture, pH and ammonia content of the litter materials. Litter samples were collected at 4^th and 8 ^th week of the experimental period.

Data collection and analysis

Data collected were subjected to a two-way analysis of variance (ANOVA), in a completely randomized design (CRD), using statistical package of social science (SPSS version 26). Significant different means were separated using Duncan New Multiple Range Test (Duncan, 1955).

Statistical Model

Y_ijk= µ + A_i+ B_j+ (Ab)_ij+ ∑ _ijk

Where;

Y_ijk= individual observation

µ = population mean

A_i= effect of rosemary

B_j= effect of bentonite

(Ab)_ij= interaction effect

∑_ijk= random effect

Results and discussion

Litter characteristics at 4 weeks of experimental period

The results of the effect of Rosemary leaf meal on litter characteristics of broiler birds at week 4 of experimental period are presented in Table 2. The result indicated that pH was significantly (p<0.05) affected by the levels of Rosemary inclusions. But, moisture and ammonia were not significantly (p>0.05) affected by the inclusion levels of Rosemary leaf meal. At higher inclusion level of 6g/kg feed, the pH decreased and as such, the pH value was high in acidity. The drop in pH value suggested that Rosemary leaf meal had significant effect on increasing the litter acidity and thereby reducing ammonia gas production. The fact that the drop is greater at higher concentrations of Rosemary showed that the effect is dependent on the inclusion levels of Rosemary leaf meal.

The results obtained in this study revealed significant decrease in pH level and in agreement with the findings of Ezenwosu and Udeh (2022), who reported that decrease in pH values of poultry litter hampered multiplication and proliferation of microorganisms and thus, reduced ammonia gas production. The pH values obtained in this study were in similar range with the findings of Maliselo and Mwaanga (2016), who reported a range in litter pH values from 6.2 to 7.8. The Findings indicated that Rosemary Leaf Meal has the ability to decrease pH and as such pH is high in acidity. The observed decrease in pH may have been due to the natural acidifying properties of Rosmarinic acid and Carsonic acid in Rosemary as reported by (Lee et al 2012). Hence these compounds may have interacted with the litter, thereby decreasing the pH level. The ideal litter pH value ranges from 6.5 to 7.6 (Mathis et al 2003). Despite the fact that ammonia was not significantly affected by the inclusion levels, the results showed a numerical reduction in the volume of ammonia gas production at 6g/kg inclusion of rosemary leaf meal, suggesting the positive effect of rosemary in the control of odour and ammonia from poultry litter.

The results of the effect of Sodium Bentonite on litter characteristics of broiler birds at week 4 of experimental period are presented in Table 3. The result indicated that pH was significant (p<0.05) decreased from 6.60 at 0g/kg feed to 4.92 at 15g/kg feed inclusion levels of sodium bentonite. The pH value decreased with an increase in sodium bentonite levels faouring acidic environment in the litter and reducing ammonia gas production. This was in line with the report of Safarikatouli et al (2011), who observed that sodium bentonited inclusion reduced litter pH levels. In another study, Bain (2009) and Ataman (2020), documented that Sodium Bentonite are clays with strong colloidal properties that absorb water quickly, which means they swell and multiply in volume creating a gelatinous substance. Reduction in litter moisture content of the litter limits microbial growth and multiplication (Pal et al (2021). Wet litter and foul odour in poultry farms are growing problems worldwide and have negative effects on the health and welfare of the birds (van der Hoeven-Hangoor 2014). Sodium bentonite improves bedding quality by enhancing mineral and protein bio-availability. It controls water activities in the litter, which invariably, determines the microbial activity (Wadud et al 2012).

The results obtained in this study revealed significant decrease in pH level. These findings were lower than ranges reported by (Dim et al 2020), who reported a slight decrease in litter pH values from 6.88 to 6.83 at 28 weeks of age. Safarikatouli et al (2011) used Sodium bentonite as feed additives in broiler diet and observed that litter pH decreases from 6.39 to 5.96 at 4 weeks of age. The findings also, indicated that Sodium Bentonite is a type of clay that have a natural acidifying properties. This acidifying properties comes from the ability to exchange cations or positively charged cations (Rihayat et al 2018). Furthermore, Sodium Bentonite has a negative charge and it can exchange Sodium ions for hydrogen ion in the litter. This exchange results in the release of hydrogen ions which decreases pH level (Abbas et al 2018). It's addition to feed is thought to have an additional benefit of slowing down feed digestibility and increase feed efficiency (Cline et al 2006). The inclusion of sodium bentonite at 15g/kg feed showed a numerical reduction in the volume of ammonia gas produced, even though that it was not statistically significant.

The results of the interaction effect of Rosemary leaf meal and Sodium Bentonite on litter characteristics of broiler birds at 4 week of experimental period are presented in Table 4. The results indicated that pH was significantly (p<0.05) influenced across the treatments, while, moisture and ammonia contents were not significantly (p>0.05) affected by the inclusion levels of Rosemary and Sodium Bentonite. The litter pH values obtained in this study were in similar range with the values reported by Safaeikatouli et al(2011), who used four Inclusion levels of Sodium Bentonite inclusions (0kg, 15kg, 30kg and 45kg) and obtained the litter pH decrease from 6.39 to 5.96. In another study, Ezenwosu and Udeh(2022) reported that values of litter pH decreased from 10.67 to 5.53, as the inclusion level of Kaolin increased. The results of this study indicated that Rosemary leaf meal and Sodium Bentonite have synergetic effects on litter pH, such that the combined effect is greater than the individual effects. Studies have shown that Rosemary contains phenolic compounds which perform antioxidant activities and helped to neutralize harmful radicals in the body and protects broiler against oxidative stress (Nietoet al 2018). Rosemary which was also reported to have antimicrobial properties, must have modulated the microbial load in the gut, thereby reducing microbial activities in the litter.

Litter characteristics at 8 weeks of experimental period

The results of the effect of Rosemary leaf meal on litter characteristics of broiler birds at 8 weeks of experimental period are presented in table 5. The results indicated that pH and ammonia content are significantly (p<0.05) affected by the levels of Rosemary inclusion, while, moisture content of the litter was not significant (p>0.05). The pH level decreased from 7.75 to 6.07, as the inclusion level of Rosemary increased from 0 to 6g/kg feed. Similarly, ammonia content of the litter decreased from 11.18 to 9.62ppm. Moisture content was not significantly affected (p>0.05), but, there was numerical reduction from 17.40 to 16.60%. The litter pH values in this study at 8 weeks of study were lower than 8.4, reported by Tabler et al (2020), who studied broiler litters on 3 years basis at University of Arkansas. In another study Miles et al (2011) reported litter ammonia of 9.1mg of Nitrogen, when he considered sand and vermiculite as litter materials in broiler production. The results obtained in this study were not in similar range with that reported by Maliselo and Mwaanga (2016), who reported an increase in ammonia to be 20 to 27ppm. The findings indicated that Rosemary Leaf Meal have the ability to decrease ammonia, because of Romarinic acid in rosemary, which inhibited the activity of urease, which is an enzyme that produces ammonia (Ghasemzadeh and Hosseinzadeh, 2020). Thus, Carsonic acid in rosemary may have bound to the ammonia making it less volatile (de Oliveira et al 2019).

The result of the Effect of Sodium Bentonite on litter characteristics of broiler birds at 8 weeks of experimental period are presented in Table 6. The results indicated that pH, moisture and ammonia content were significantly (p<0.05) affected by the inclusion levels of sodium bentonite. The results showed that the rate of pH decreased as the rate of inclusion increased. Similarly, moisture and ammonia decreased as the rate of inclusion levels of sodium bentonite increased. Consequent to previous studies, it has been noted that Sodium Bentonite improves litter characteristics and also improves broiler performance (de Toledo et al 2020). In another study Miles et al (2011) reported litter ammonia of 9.1mg of Nitrogen, when sand and vermiculite were considered as litter materials in broiler production.

The results obtained in this study were not in similar range with results reported by Dim et al (2020), who used dietary bentonite to improve the litter quality of broiler birds and reported that at 54 weeks of age, litter pH level decreased from 7.24 to 6.53 and Nitrogen level from 4.04 to 3.65. In a different study, Sahoo et al (2017), concluded that Sodium Bentonite could be used as litter material. In his study, he used Sodium Bentonite as litter material and not as feed additives. He made emphasis that keeping the litter dry is a critical point of Poultry farm management and further reported that sodium bentonite helped in reduction of moisture present in the litter; which as well reduced the amount of Ammonia present in the litter. He concluded that sodium bentonite reduced the bacteria activity that produces ammonia. Basically, litter moisture content is important because it affects the rate of microbial activity in the litter. If there's too much moisture, it can create an environment that's too wet for the microbes that break down waste, which then, can lead to increased ammonia levels. So, as sodium bentonite is causing decrease in moisture content, it could mean that they're also affecting the litter's ability to manage ammonia levels effectively. Nikolakakis et al(2013) used an inclusion level of 1.5% sodium bentonite in the diet and observed lower moisture content in the litter. Parizadian et al(2013) also observed significant reduction in moisture content of excreta and improved quality of litter after the inclusion level of 1.5% of clay (Clinoptiolite) in broiler diets and thus, confirmed that clay materials can reduce moisture content in poultry litter.

The results of the interaction effect of Rosemary Leaf meal and Sodium Bentonite on litter characteristics of broiler birds at 8 weeks of experimental period are presented in Table 7: The result indicated that pH, moisture and ammonia contents were significantly (p<0.05) affected by the test materials. The interaction of rosemary leaf meal and sodium bentonite significantly (p<0.05) decreased pH value from 7.80 to 6.23, moisture content of the litter from 16.47 to 13.73% and ammonia content of the litter from 12.37 to 8.13ppm, at inclusion level of 3g/15g per kg feed. The interaction of Rosemary and Sodium Bentonite could have created some unexpected chemical reactions that affected the pH, moisture and ammonia contents of the litter. It could be possible that the inclusion levels of the two additives come into play, even though, the combination may have different effects at different concentrations, but, the combined effects gave significant reductions across the parameters. These results of this study were in agreement with Hafez et al (2016) who reported that poultry litter moisture, pH and ammonia contents were reduced by rosemary leaf meal inclusions. Miles et al (2004) reporting on the negative effect of moisture, stated that presence of high moisture in poultry litter leads to clumping or caking of the litter, which culminates to increased ammonia level in the litter. In similar vein, Wathes (2000) reported that increased ammonia level in poultry litter causes toxicity and constitute health challenges on the poultry birds.

Conclusion

• It was concluded that inclusion of 15g SB and 3g RLM per kg feed improved litter characteristics by reducing ammonia gas, moisture and pH levels
  
  
• Controlled odour production in the broiler birds’ litter
  
  
•  Recommended that 15g SB and 3g RLM should be used by farmers to improve litter characteristics in order to reduce ammonia gas production and control odour in poultry houses, hence, maintain environmental friendliness.

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