Effect of lanthanide citrate and cerium citrate supplementation on performance of broilers

Introduction

The poultry industry represents one of the most rapidly expanding sectors within Indian agriculture, contributing significantly to food production, employment generation, and the national economy. To enhance poultry productivity and health, various feed additives are routinely incorporated into diets. These additives facilitate improved growth rates, feed efficiency, and overall performance, while also aiding in disease management. In recent years, rare earth elements (REEs) have garnered attention as potential alternatives to antibiotic growth promoters in animal nutrition. REEs encompass elements such as lanthanum, cerium, scandium, yttrium, and several related elements naturally present in the Earth's crust (Redling, 2006) [21] . Among these, lanthanum and cerium have been the focus of extensive study in livestock and poultry nutrition. Prior research indicates that these elements can enhance body weight gain, feed conversion efficiency, egg production, milk yield, and general growth performance. The beneficial effects are attributed to their antimicrobial and antioxidant properties, enhanced enzyme activity, strengthened immune responses, and improved digestion and nutrient absorption. (He and Rambeck, 2000; Cai et al., 2018) [11,7] . Although REEs share similar chemical characteristics, lanthanum and cerium exhibit distinct biological functions. Lanthanum typically exists in a single stable oxidation state, whereas cerium can exist in two oxidation states, enabling participation in redox reactions and contributing to antioxidant activity (Zhang et al., 2019) [23] . Given their ionic radii are comparable to calcium and other metal ions, these elements may influence metabolic pathways and cellular processes (Cai et al., 2018) [7] . Evidence suggests that organic forms, such as lanthanum citrate and cerium citrate, are more efficacious than their inorganic counterparts (He and Rambeck, 2000; He et al., 2010) [11,12] . Supplementation with these organic compounds has been associated with enhanced growth performance, nutrient utilization, and metabolic activity in non-ruminant species. (Kraatz et al., 2006; Forster et al., 2008; Cai et al., 2015) [17,10,7] . Citric acid and its salts, including lanthanum citrate and cerium citrate, also confer benefits to the digestive system by lowering gastrointestinal tract pH. This acidification inhibits the proliferation of pathogenic bacteria such as Escherichia coli and Salmonella. Additionally, these compounds stimulate digestive enzyme activity, improve mineral bioavailability, support gut health, and augment nutrient utilization. (Boling-Frankenbach et al., 2001; Nourmohammadi et al., 2012; Islam, 2012; Wu et al., 2024) [4, 19, 14, 22] . Despite encouraging outcomes observed in other animal species, data on the application of rare earth element citrates in poultry remain limited. Accordingly, the present study was undertaken to assess the effects of varying dietary levels of a lanthanum citrate and cerium citrate combination on the growth performance of broiler chickens. The study aimed to establish the potential of these compounds as safe and sustainable growth-promoting feed additives in broiler production.

Materials and Methods

The experiment was conducted over a period of 35 days at the Department of Poultry Science, Mumbai Veterinary College, Goregaon, Mumbai. A total of 360 one-day-old Vencobb 430Y broiler chicks were utilized in the study. The birds were randomly allocated into six groups, each comprising 60 chicks. Each group was further subdivided into six replicates, with 10 birds per replicate. The six groups were subsequently assigned distinct dietary treatments to evaluate the effects of the feed supplements. Group A: Control diet as per the strain standards Group B: Control diet supplemented with lanthanide citrate and cerium citrate @ 50 g/T of feed Group C: Control diet supplemented with lanthanide citrate and cerium citrate @ 70 g/T of feed Group D: Control diet supplemented with lanthanide citrate and cerium citrate @ 90 g/T of feed Group E: Control diet supplemented with lanthanide citrate and cerium citrate @ 110 g/T of feed Group F: Control diet supplemented with lanthanide citrate and cerium citrate @ 120 g/T of feed All experimental groups were maintained under uniform conditions throughout the duration of the study. The birds were provided with ad libitum access to feed and clean drinking water and were reared on a deep litter system under consistent environmental and management practices. The diets were formulated in accordance with the nutritional requirements recommended for the Vencobb 430Y broiler strain. Distinct feed formulations were administered during the pre-starter, starter, and finisher growth phases. Details of the feed composition utilized in the experiment are presented in Table 1. The nutrient composition of the prestarter, starter, and finisher diets was determined through proximate analysis, following the procedures outlined by the AOAC (2016) [3] , with the results summarized in Table 2.

Results

Live weights

The average weekly body weights of birds across different groups, from day-old to five weeks of age, are presented in A, B, C, E, andD. However, the differences in weekly body weights among the groups were not statistically significant (p≥0.05).

A comparable trend was observed for weight gain, with Group F demonstrating the greatest overall weight gain; nevertheless, the differences among groups were not statistically significant (p≥0.05). These results are consistent with those reported by He et al. (2010) [12] , who noted a numerical increase in body weight in broilers fed diets supplemented with rare earth element (REE) chlorides at 70 mg/kg and REE citrate at 70 and 100 mg/kg relative to the control group. Similarly, Agbede et al. (2011) [2] observed only modest improvements in body weight following supplementation with lanthanum oxide (La₂O₃) at levels of 100, 200, and 300 ppm. Likewise, Jo et al. (2009) [15] reported increased cumulative weight gain in birds supplemented with cerium (100 ppm) and lanthanum (100 ppm), individually or in combination, though these differences were not statistically significant (p≥0.05).

Conversely, Mijgar et al. (2025) [18] demonstrated that supplementation with lanthanum citrate at 70 mg/kg significantly increased body weight (P≤0.01) compared to the control group. Similarly, Song and Park (2007) [6] reported a significant enhancement (P≤0.01) in cumulative weight gain when REEs were incorporated at 100 ppm. He et al. (2010) [12] further explored the mechanisms by which rare earth elements enhance performance in monogastric animals. Ou et al. (2000) [20] proposed that REEs may exert their effects through various biological mechanisms, including increased enzyme activity, improved nutrient utilization, and enhanced secretion of digestive fluids. Their findings indicated that the inclusion of small quantities of organic or inorganic REEs in broiler diets can contribute to improved growth performance.

Feed consumption

The average weekly feed intake of birds across different groups from the first to the fifth week is presented in Table 4. The total feed consumption per bird over the entire fiveweek period was 3228.58±44.74, 3165.78±57.51, 3144.57±47.07, 3129.20±52.62, 3132.78±31.47, and 3218.09±49.45 grams for Groups A to F, respectively. Among all groups, birds in Group A exhibited the highest feed intake, followed by Groups F, B, C, E, and D. However, the differences in feed intake among the groups were not statistically significant (p≥0.05). These findings are consistent with those of Mijgar et al.

(2025) [18] , who reported no significant differences in weekly feed intake among broilers supplemented with lanthanum citrate at 70 and 140 mg/kg. Similarly, Jo et al. (2010) [16] observed that the inclusion of rare earth elements at 500 ppm in broiler diets did not significantly affect feed consumption. Durmus and Bolukbasi (2015) [8] also reported that supplementation with 400 mg/kg lanthanum oxide in laying hens had no significant impact on feed intake. In accordance, Bolukbasi et al. (2016) [5] found that dietary inclusion of cerium oxide at levels of 100, 200, 300, and 400 mg/kg in laying hens did not significantly influence feed intake.

Feed conversion ratio

The average weekly feed conversion ratio (FCR) of birds from the various treatment groups during the first to fifth weeks is presented in Table 5. The cumulative FCR values at the end of the five-week period for Groups A to F were 1.408±0.01, 1.408±0.02, 1.400±0.01, 1.397±0.01, 1.397±0.01, and 1.396±0.01, respectively. The results demonstrate that birds in Group F, which received a diet supplemented with lanthanide citrate and cerium citrate at 120 g per ton, exhibited a 0.85% improvement in FCR compared to Group A. Similarly, birds in Groups D and E showed a 0.78% enhancement in FCR relative to Group A. However, these differences in FCR among the groups were not statistically significant (p≥0.05). These findings align with those of Eleraky and Rambeck (2011) [11] , who reported improved FCR in quails supplemented with REE-citrate at 50, 100, and 200 mg/kg, although the differences were not significant (p≥0.05). Jo et al. (2010) [16] similarly observed no significant effect on FCR in birds fed diets containing various rare earth elements and colloidal silver. In contrast, Mijgar et al. (2025) [18] reported a significant improvement in feed conversion ratio with the supplementation of lanthanum citrate at 70 mg/kg.

Mortality

At the conclusion of the five-week period, the mortality rates for Groups A to F were 3.26%, 1.63%, 0%, 0%, 4.91%, and 1.63%, respectively. Overall, mortality levels across all groups remained within the normal range, indicating that the various treatments did not adversely affect the health of the birds.

European production efficiency factor

The average European Production Efficiency Factor (EPEF) at the end of five weeks was 386.39, 402.90, 411.67, 403.28, 385.87, and 403.36 for Groups A, B, C, D, E, and F, respectively (Fig. 1). The results indicate that birds in Group C exhibited the highest EPEF, followed by Group F, which received lanthanide citrate and cerium citrate at 120 g per ton. Groups B and D, supplemented with 50 g/T and 90 g/T respectively, also demonstrated higher EPEF compared to the control Group A. However, these differences in EPEF among the groups were not statistically significant (p≥0.05). Limited research is available regarding the impact of lanthanide citrate and cerium citrate on EPEF. Nonetheless, in the present study, the diet supplemented with 90 g/T of these additives yielded the most favorable EPEF performance in broiler production. X-axis represents the different groups from A to F and Y-axis represents the European production efficiency factor (EPEF) of the birds.

Conclusion

Lanthanide citrate and cerium citrate can be seen as potential new feed additives. The results of this study, based on different growth parameters, suggest that adding 120 g/T of these compounds to broiler diets may help improve overall growth performance.

Acknowledgement

AcknowledgmentsI wish to express my sincere gratitude to Dr. Bainabi Pramanik, Technical Sales at Chemet 201, for providing the Lancer product (lanthanide citrate and cerium citrate), which is manufactured by Treibacher Industrie AG and distributed by Chemet.

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