6. Replacing dried fish with fresh water spinach for growing pigs fed whole sugar cane stalks or cane juice

Authors: Sorn Suheang and Preston, 2005.

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Summary : The experiment was conducted at CelAgrid, in Kandal province in Cambodia , about 25 km from Phnom Penh city. The average annual temperature in this farm was morning 25 o C (midday 30 o C and afternoon 27.5 o C). The experiment began on 20 June and finished on 28 September, 2004. A total of 32 pigs were used in the experiment. The design was a 2*4 factorial arrangement with 2 replicates using 16 castrate male pigs with average initial live weight 13.1 kg and 16 females with average initial live weight 12.7kg. The pigs were allocated to 8 pens in groups of two (one male and one female), and each pen assigned to the treatments within blocks (replicates) according to live weight. The two factors were: processing of sugar cane (chopped whole cane stalk and sugar cane juice) and level of protein from dried fish (50,100,150 and 200g/day). The pigs were housed in pens (1.82*2.0m) with concrete floors in an open-sided shed thatched with dry leaves. Every pen had a feed trough and a drinking nipple to provide water ad libitum. The sugar cane was purchased every 2 to 3 days from farmers or from the local market. Dried whole fish were purchased in the local market. Whole sugar cane (WC) was chopped with a knife in lengths of about 4cm and offered at 200 g/kg lives weight (fresh basis). This level was similar to that used by Bravo et al (1996). The sugar cane juice (SCJ) was obtained by crushing sugar cane stalks in a 3-roll crusher. The juice was fed free choice to the point where refusals were minimal. In treatments DF75, DF50 and DF25, the water spinach was offered ad libitum in amounts of about 20% over the recorded intake. The dried whole fish was given as the first feed at 7.30am in the feed trough, followed by the water spinach (treatments DF75, DF50 and DF25) which was chopped in small pieces (3-4 cm).The hand-chopped sugar cane stalks were fed on the floor of the pen at the same time as feeding the water spinach. The sugar cane juice was fed in the troughs after the pigs had consumed the dried fish. Every day, feed refusals were recorded. The extraction rate (liters juice from 100 kg cane stalk), the brix value and the DM content of the cane, were measured daily and the values averaged over weekly periods. Feeds offered and refused were weighed daily (scale of 1±0.005 kg for dried fish; of 10 ±0.5kg for sugar cane and water spinach). The animals were weighed every 10 days (scale of 100 kg±1.00 kg). The duration of the experiment was 100 days. Samples of feeds and refusals were analysed for DM by micro-wave radiation (Undersander et al., 1993) and for nitrogen and ash by AOAC, (1990). The composition of the sugar cane juice was determined with a hand refractometer which measured the “brix”, which is equivalent to total sugar content. The DM content was considered to be the same as ”brix” value.

Abstract : Whole sugar cane stalk and sugar cane juice were used as the sources of energy, and the dried fish with the level of 50, 100, 150 or 200 g protein per day were fed to pigs. Fresh water spinach was chopped and fed ad libitum on the diets with 50, 100 and 150 g protein from dried fish. The whole sugar cane stalks at 40 cm lengths were offered at 200 g/kg live weight, while the juice was fed ad libitum. The processing of sugar cane and the level of dried fish did not affect the daily DM intake. Final daily live weight gain increased (P<0.02) as the level of fish protein was increased from 50 to 100 and 150 g/pig. There was no interaction between processing of the sugar cane and the level of fish protein on growth rate or conversion.

it is concluded that the water spinach can provide a major part of the protein to replace dry fish for growing pigs fed sugar cane juice or sugar cane stalk.