Evaluasi Pemanfaatan Zat Besi Organik (Fe) dalam Kandungan Pakan terhadap Kinerja Pertumbuhan dan Kesehatan Ikan Lele (Clarias gariepinus)

Abstract

Zat besi (Fe) merupakan salah satu mikromineral esensial yang berperan penting dalam berbagai proses fisiologis pada ikan, antara lain sebagai komponen hemoglobin dan mioglobin dalam transportasi serta penyimpanan oksigen, kofaktor berbagai enzim yang terlibat dalam metabolisme energi, sintesis DNA, respirasi seluler, sistem kekebalan tubuh, dan mekanisme pertahanan antioksidan. Ketersediaan Fe yang memadai diperlukan untuk menunjang eritropoiesis, menjaga keseimbangan metabolisme, serta mendukung pertumbuhan dan kesehatan ikan. Namun, keseimbangan kandungan Fe dalam pakan harus diperhatikan karena defisiensi maupun kelebihan Fe dapat menimbulkan dampak negatif terhadap performa fisiologis ikan. Defisiensi Fe menyebabkan gangguan pembentukan eritrosit, penurunan kadar hemoglobin, anemia, dan penurunan pertumbuhan, sedangkan kelebihan Fe meningkatkan pembentukan reactive oxygen species (ROS) yang memicu stres oksidatif dan kerusakan jaringan. Fe dalam bentuk organik memiliki ketersediaan hayati (bioavailability) yang lebih tinggi dibandingkan bentuk anorganik sehingga lebih efisien diserap dan dimanfaatkan oleh tubuh ikan. Meskipun demikian, informasi mengenai dosis optimal suplementasi Fe organik pada ikan lele (Clarias gariepinus) masih terbatas. Oleh karena itu, penelitian ini bertujuan mengevaluasi pengaruh suplementasi Fe organik dalam pakan terhadap performa pertumbuhan, efisiensi pemanfaatan pakan, status hematologi, respons imun non-spesifik, sistem antioksidan, distribusi Fe dalam tubuh, serta kondisi fisiologis dan histologis organ ikan lele. Penelitian dilaksanakan selama 60 hari menggunakan rancangan acak lengkap (RAL) dengan lima taraf suplementasi Fe organik, yaitu 0, 20, 40, 80, dan 160 mg kg?¹ pakan, masing-masing terdiri atas empat ulangan. Ikan lele berukuran 9–10 cm dipelihara dengan kepadatan 15 ekor per akuarium berukuran 45 × 30 cm dan diberi pakan dua kali sehari menggunakan metode at satiation. Kualitas air dipertahankan melalui pergantian air secara bertahap selama pemeliharaan. Parameter yang diamati meliputi performa pertumbuhan, efisiensi pemanfaatan pakan, status hematologi, respons imun non-spesifik, sistem antioksidan setelah uji tantang hipoksia, kandungan Fe tubuh, serta histologi hati dan morfometri vili usus. Hasil penelitian menunjukkan bahwa suplementasi Fe organik memberikan pengaruh nyata terhadap pertumbuhan, efisiensi pemanfaatan pakan, status hematologi, respons imun, sistem antioksidan, kandungan Fe tubuh, serta kondisi histologis organ. Dosis 40 mg kg?¹ pakan memberikan respons terbaik dengan meningkatkan bobot akhir hingga 122,32% dibandingkan kontrol, disertai peningkatan biomassa, laju pertumbuhan spesifik, efisiensi protein, dan retensi protein serta penurunan rasio konversi pakan. Perlakuan tersebut juga meningkatkan kadar hemoglobin, jumlah eritrosit, dan hematokrit, dengan nilai MCV lebih rendah serta MCH dan MCHC tetap normal yang menunjukkan kondisi eritrosit yang lebih baik. Aktivitas respiratory burst, lisozim, SOD, dan CAT meningkat, sedangkan kadar MDA menurun, menunjukkan peningkatan kapasitas imun dan sistem pertahanan antioksidan. Selain itu, dosis optimal mampu mempertahankan integritas jaringan hati dan meningkatkan morfometri vili usus sehingga mendukung absorpsi nutrien. Sebaliknya, suplementasi Fe organik sebesar 160 mg kg?¹ pakan meningkatkan akumulasi Fe dalam jaringan, meningkatkan kadar MDA, menyebabkan peningkatan MCV dan penurunan MCHC yang mengindikasikan anemia fungsional, serta menimbulkan perubahan histologis pada hati dan usus akibat stres oksidatif. Berdasarkan hasil penelitian dapat disimpulkan bahwa suplementasi Fe organik dalam pakan berpengaruh signifikan terhadap performa pertumbuhan, efisiensi pemanfaatan pakan, status hematologi, respons imun non-spesifik, sistem antioksidan, distribusi Fe dalam tubuh, serta kondisi fisiologis dan histologis organ ikan lele (Clarias gariepinus). Dosis suplementasi Fe organik sebesar 40 mg kg?¹ pakan merupakan dosis optimal karena mampu meningkatkan pertumbuhan, memperbaiki efisiensi pemanfaatan pakan, meningkatkan kapasitas transportasi oksigen, memperkuat sistem imun dan antioksidan, serta mempertahankan integritas organ tanpa menyebabkan akumulasi Fe yang berlebihan. Temuan ini menunjukkan bahwa suplementasi Fe organik pada dosis yang tepat berpotensi diterapkan sebagai strategi nutrisi untuk meningkatkan produktivitas dan kesehatan ikan lele dalam budidaya secara berkelanjutan.

Iron (Fe) is an essential trace mineral that plays a crucial role in various physiological processes in fish, including serving as a component of hemoglobin and myoglobin for oxygen transport and storage, acting as a cofactor for enzymes involved in energy metabolism, DNA synthesis, cellular respiration, immune function, and antioxidant defense mechanisms. Adequate Fe availability is essential to support erythropoiesis, maintain metabolic homeostasis, and promote optimal growth and health in fish. However, maintaining an appropriate dietary Fe balance is critical because both deficiency and excess can adversely affect fish physiological performance. Iron deficiency impairs erythrocyte formation, reduces hemoglobin concentration, causes anemia, and suppresses growth, whereas excessive Fe promotes the formation of reactive oxygen species (ROS), leading to oxidative stress and tissue damage. Organic Fe has higher bioavailability than inorganic Fe, resulting in more efficient absorption and utilization by fish. Nevertheless, information regarding the optimal dietary level of organic Fe supplementation for African catfish (Clarias gariepinus) remains limited. Therefore, this study aimed to evaluate the effects of dietary organic Fe supplementation on growth performance, feed utilization efficiency, hematological status, non-specific immune response, antioxidant defense system, body Fe distribution, and the physiological and histological conditions of African catfish. The experiment was conducted for 60 days using a completely randomized design (CRD) consisting of five dietary organic Fe supplementation levels: 0, 20, 40, 80, and 160 mg kg?¹ diet, with four replicates per treatment. African catfish with an initial length of 9–10 cm were stocked at a density of 15 fish per aquarium (45 × 30 cm) and fed twice daily using the at satiation feeding method. Water quality was maintained through periodic partial water exchange throughout the experimental period. The evaluated parameters included growth performance, feed utilization efficiency, hematological indices, non-specific immune responses, antioxidant defense system following a hypoxia challenge test, body Fe content, liver histology, and intestinal villus morphometry. The results demonstrated that dietary organic Fe supplementation significantly affected growth performance, feed utilization efficiency, hematological status, immune response, antioxidant capacity, body Fe accumulation, and tissue histology. Supplementation with 40 mg kg?¹ diet produced the most favorable biological responses, increasing final body weight by 122.32% compared with the control, accompanied by improvements in biomass, specific growth rate, protein efficiency, protein retention, and feed conversion ratio. This treatment also increased hemoglobin concentration, erythrocyte count, and hematocrit value, while producing lower mean corpuscular volume (MCV) with normal mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC), indicating healthier erythrocyte characteristics. Furthermore, respiratory burst activity, lysozyme activity, superoxide dismutase (SOD), and catalase (CAT) activities were significantly enhanced, whereas malondialdehyde (MDA) concentration was reduced, indicating improved innate immune function and antioxidant defense. Histological observations revealed that the optimal Fe supplementation maintained liver integrity and improved intestinal villus morphometry, thereby supporting more efficient nutrient absorption. In contrast, supplementation with 160 mg kg?¹ diet resulted in excessive Fe accumulation in tissues, elevated MDA levels, increased MCV, decreased MCHC indicative of functional anemia, and histopathological alterations in the liver and intestine associated with oxidative stress. In conclusion, dietary organic Fe supplementation significantly influences growth performance, feed utilization efficiency, hematological status, non-specific immune response, antioxidant defense system, body Fe distribution, and the physiological and histological conditions of African catfish (Clarias gariepinus). Supplementation with 40 mg kg?¹ diet was identified as the optimal dosage, as it enhanced growth, improved feed utilization efficiency, increased oxygen transport capacity, strengthened immune and antioxidant defenses, and maintained tissue integrity without causing excessive Fe accumulation. These findings suggest that appropriate dietary organic Fe supplementation represents a promising nutritional strategy to improve the productivity, health, and physiological balance of African catfish under aquaculture conditions.