Pengaruh suplementasi selenium, metionin, dan iodium terhadap pertumbuhan dan kecerdasan anak tikus dari induk kekurangan iodium

Abstract

Gangguan Akibat Kekurangan Iodium yang masih merupakan salah satu masalah utama gizi masyarakat Indonesia dan masalah utama gizi masyarakat dunia perlu segera dipecahkan (DepKes RI, 1998; WHO, 1995). Iodotironin-5'-deiodinase tipe I yang mengatalisasi perubahan T 4 menjadi T 3 dan glutation-peroksidase yang masing-masing mengandung selenium dan sistein, sangat berperan dalam sintesis dan diferensiasi protein (Combs and Combs, 1986; Arthur et al., 1993; Combs, 1999). Informasi tersebut menunjukkan bahwa selenium, metionin, dan iodium diduga sating berinteraksi mempengaruhi pertumbuhan dan kecerdasan. Penelitian ini bertujuan untuk menentukan dosis suplementasi selenium, metionin, dan iodium yang mempengaruhi pertumbuhan dan kecerdasan optimum anak tikus dari induk kekurangan iodium. Penelitian terdiri dari dua percobaan. Percobaan pertama yang dilaksanakan dari bulan Nopember 1996 sampai Juni 1997, menggunakan tikus keturunan galur wistar umur 95 hari yang diberi ransum basal cukup enerji tetapi kurang protein dan kurang iodium. Rendahnya tingkat reproduksi (78%) dan tingkat kelangsungan hidup (70%) serta tingginya angka kematian (22%) anak tikus pada percobaan pertama mendorong dilaksanakannya percobaan kedua. Percobaan kedua yang dilaksanakan dari bulan Nopember 1997 sampai Juni 1998, menggunakan tikus keturunan galur wistar umur 95 hari yang diberi ransum basal cukup enerji dan cukup protein tetapi kurang iodium.

The objective of this research is to study the effect of selenium, methionine and iodine supplementation on optimal growth and intelligence of young rats derived from rats with iodine deficiency. This research was conducted at the Diponegoro Unit Research Station, Ministry of Health, 6 Salemba Jakarta, from November 1996 until June 1997 (Exp 1) and Nopember 1997 until June 1998 (Exp 2). Recent but unequivocal finding suggested that the effective utilization of iodine depended on the selenium-containing enzyme Type I Iodothyronine-5' -Deiodinase, IOI, and thus utilization of iodine was influenced by selenium status. Selenium and methionine are two essential component of ID-I; therefore in this research selenium, methionine and iodine were supplemented in the diet. The research comprised of two experiments: 1) the experimental rats were fed diets containing adequate energy but low protein and low iodine (Exp I), 2) the experimental rats were fed diets containing adequate energy and protein but low iodine (Exp 2). Exp 2 was conducted due to the low productivity (78%) and high mortality (22%) of the young rats in Exp 1. A complete randomized design with three factorial treatments i.e. three supplementation levels of selenium (0.000, 0.046, 0.092 ppm), methionine (0, 350, 700 ppm) and iodine (0.000, 0.153, 0.306 ppm), with three replicates for each treatment; therefore there were 27 combination of treatment diets in each experiment. There were two control groups in Exp 1: A negative control group fed basal diet with no supplementation, and a commercial group fed commercial diet. There were three control groups in Exp 2: A negative control group fed basal diet with no supplementation, a commercial control group fed commercial diet and a positive control group fed basal diet supplemented with selenium, methionine and iodine according to the requirement level. The wistar derived rats used in these experiments were fed commercial diets since they were born. By the age of 95 days the rats were fed basal diet. Starting from the age of I 02 days up to partus, each treatment group were fed one of the 27 combination treatment diets. Until the age of 42 days, the young rats were fed the same diets as their mothers'.