Performa produksi dan reproduksi domba garut yang mendapat ransum bersuplemen kromium, kalsium dan bernilai kation anion berbeda

Abstract

Chromium (Cr) is an essential mineral for ruminants. Its metabolism and interactions with other minerals has not been widely known. Besides that chromium mineral and cation-anion balance in ration affects acid-base balance and mineral metabolism in body liquid. Changes in the acidity of body liquid indirectly affect the characteristics of animal production and reproduction. Two experiments were conducted to assess the production and reproduction performance of Garut sheep offered rations with different dietary cation anion balance (DCAB) and supplemented with chromium (Cr) and calcium (Ca). In the first experiment four dietary treatments, namely: R0 (basal diet); R1 (R0+Cr 3 ppm), R3 (R0+ Ca); R3 (R2+ Cr 3 ppm), were allocated in twenty four of 1.5-2 years old Garut grade rams in a randomized block design. Albumin separation method was used to separated X and Y spermatozoa of Garut sheep. In the second experiment, treatments consisted of combinations of mating patterns and pregestating rations, namely: Ram R3 (Cr + DCAB 0) x Ewe R0 (DCAB +14) (RJA); Ram R1 (Cr+ DCAB+14) x Ewe R2 (Cr + DCAB-10) (RBA); Ram R0 (DCAB+14) x Ewe R0 (DCAB+14) (RJBB). In the first experiment, the results showed that Cr supplementation in rations containing different levels of Ca did not affect feed intake, body weight gain, and dry matter digestibility, but reduced the absorption of Cr and also the absorption of Ca of the low Ca diet. The increased of Cr intake decreased the absorption of Cr. Supplementation of Cr had no effect on Cr, Ca, Zn, and Mg status in blood and semen of the rams. Intake of Cr and Ca were not related to the semen Cr and Ca levels. However Level of Cr intake tended to correlate negatively with the Cr absorption and correlate positively with blood Cr levels. There was a positive relationship between the level of Ca intake with the Ca and Mg absorption and blood Ca and Zn levels. The results showed that Cr supplementation in the ration with different level of Ca and dietary cation anion balance (DCAB) not affect the rectal temperature as well as in respiration rate of Garut rams. Supplementation of Cr in the ration does not affect semen quality of Garut rams either macroscopically or microscopically. Supplementation of Cr in ration containing acid DCAB reduced semen pH and membrane integrity the lower fraction spermatozoa on day 49. In the second experiment, results showed that there was a close relationship between gestational periods and body weight gain of gestating ewes. Cr supplementation and DCAB reduction in ram and ewe pre-gestating rations did not affect gestational periods. Lambs number of the same birth from Cr and DCAB10-supplemented ewes mated with Cr-supplemented rams tended to increase. Sex ratio of offspring from ewes mated with Cr and DCAB 0-supplemented rams tended to decrease.

Kromium (Cr) adalah mineral penting bagi ternak ruminansia. Metabolisme dan interaksi mineral Cr belum banyak diketahui. Namun demikian beberapa laporan menunjukkan peranannya dalam metabolisme karbohidrat, protein dan lemak. Suplementasi garam mineral kromium dan mineral makro lainnya dapat mempengaruhi keseimbangan kation dan anion cairan tubuh, yang pada akhirnya akan mempengaruhi keseimbangan asam basa cairan tubuh. Suplementasi garam mineral Cr juga akan mempengaruhi metabolisme mineral lainnya. Keseimbangan kation anion dalam tubuh dapat dipengaruhi melalui pengaturan kadar natrium (Na), kalium (K), khlor (Cl), dan sulfur (S) ransum yang disebut neraca kation anion ransum (NKAR). Penelitian ini bertujuan untuk mengkaji manfaat suplementasi Cr pada ransum dengan nilai NKAR dan berkadar Ca berbeda. Domba Garut yang prolifik digunakan sebagai model untuk mengkaji performa produksi dan reproduksi sebagai respon terhadap suplementasi Cr pada ransum dengan nilai NKAR dan Ca berbeda. Penelitian ini terdiri atas dua tahap percobaan. Percobaan pertama adalah mengkaji performa produksi, metabolisme mineral dan kualitas semen domba Garut. Percobaan menggunakan 24 ekor domba Garut Jantan berasal dari Sumedang berumur ± 1.5 tahun dengan bobot badan 32.02±3.71 kg. Ransum perlakuan terdiri atas: R0 (ransum basal); R1 (R0+Cr 3 ppm); R2 (R0+Ca); R3 (R2+Cr 3 ppm), menggunakan rancangan acak kelompok (RAK). Mineral Cr yang digunakan adalah Cr yang terinkorporasi dalam kacang kedele selama proses fermentasi tempe oleh ragi (ragi kaya Cr). Separasi spermatozoa menggunakan metoda separasi albumin telur. Percobaan kedua adalah mengkaji pola kelahiran anak domba Garut. Sebanyak 17 ekor domba betina umur 20-30 bulan dengan bobot badan awal 30.3±1.98 kg digunakan untuk percobaan ini. Setiap ekor domba betina dikawinkan dengan salah satu dari 3 pejantan yang telah diberi ransum perlakuan selama 49 hari dari percobaan pertama. Perlakuan pada penelitian ini adalah pola perkawinan berdasarkan perbedaan jenis ransum yang diberikan kepada jantan dan betina sebelum bunting. Pola perkawinan domba tersebut adalah sebagai berikut: (1) Perkawinan RJA: Domba Jantan R3 (Cr+NKAR 0) x Domba betina R0 (NKAR +14); (2) Perkawinan RBA: Domba Jantan R1 (Cr+NKAR +14) x Domba betina R2 (Cr+NKAR -10); (3) Perkawinan RJBB: Domba Jantan R0 (NKAR +14) x Domba betina R0 (NKAR +14).