Ensiled taro foliage replacing rice bran in diets of gilts during pregnancy and lactation

Chhay Ty, Khieu Borin and T R Preston*

Center for Livestock and Agriculture Development.
Pras Teat village, Rolous commune, Kandal Stung district, Kandal province. PO Box 2423 Phnom Penh 3, Cambodia
chhayty@celagrid.org
* Center for Research and Technology Transfer, Nong Lam University, Ho Chi Minh City, Vietnam

Abstract

Ten crossbred gilts (Large White*local breed), with an average body weight of 122±4.62 kg were mated by AI with semen from a Pietrain boar and followed for one complete reproductive cycle, during which they received diets of rice bran replaced by ensiled Taro (Colocacia ensiformis) foliage at levels (DM basis) of  0, 15, 30, 45 and 60% .  The experimental diets were offered three weeks after mating. Feeding was 2% of live weight (DM basis) during pregnancy and ad libitum during lactation.

There were  curvilinear responses in intake of DM and crude protein during gestation and lactation with the maximum values recorded with 30% taro foliage silage in the diet DM. Weight gain of the gilts during pregnancy increased as taro foraage silage was raised to the 30% level with no further increase up to 60% taro silage.  Feed conversion ratio showed a positive linear  response to level of taro foliage silage.  Less live weight was lost during lactation as rice bran was replaced by with ensiled taro foliage, with optimum values at 45 and 60%  levels of ensiled taro foliage in the diet. The number of piglets born was lowest on the 100% rice bran diet and highest with 60% replacement by Taro silage. The total litter weight at birth did not difffer among treatments as weights of the piglets reflected the size of the litter. Litter weights at weaning did not differ among treatments. Overall feed conversion (feed consumed during gestation and lactation per kg piglet weaned) appeared to improve as the proportion of taro silage in the diet was inceased.

Diets composed of approximately equal parts (DM basis) of ensiled taro foliage and rice bran supported satisfactory reproduction and lactation in crossbred gilts.

Key words: foliage silage, rice bran

Introduction

Pig production for small producers is usually a secondary source of family income, and used for festive events, paying a debt or as a savings bank. It is concentrated in rice growing areas because it is dependent on by-products from rice such as rice bran and broken rice. The constraint to use of these energy-rich byproducts is the need for protein supplements, which in conventional form (soybean meal and fish meal) are difficult to acquire in rural areas as well as being expensive. For this reason emphasis has been put on the use of protein-rich foliages which can be grown by the farmer ( http://www.mekarn.org/proprf/content.htm). Taro (Colocasia esculenta L Shott) is found growing in the wild state in mountain areas, in forests and in ponds and other water surfaces (Pham Sy Tiep et al 2006; Ngo Huu Toan and Preston 2007; Pheng Buntha et al 2008). The survey in Cambodia by Pheng Buntha et al (2008) indicated that farmers grew taro mainly for tuber production but they occasionally fed the leaves and petioles to their pigs. Cooking of the taro foliage was considered to be necessary in view of the irritation (itching) on the skin and in the mouth of the pigs caused by contact with the fresh leaves.

Objective

The objective in the study was to evaluate the effect of different levels of ensiled taro foliage replacing diet rice bran on performance of gilts during pregnancy and lactation .

Materials and methods

Location

The experiment was carried out in the Center for Livestock and Agriculture Development (CelAgrid), located in Phras Teat village, Sangkat Rolous, Khan Dankor, about 25km from Phnom Penh City, Cambodia.

Experimental animal, treatments and design

Ten crossbred (Large white x Local breed) gilts , with an average live body weight of 122±4.62 kg were housed in individual pens with concrete floor. The experiment was done according to a Completely Randomized Design (CRD) with 5 treatments and 2 replications of each treatment. The gilts were were mated by AI with semen from the Pietrain boar and followed for one complete reproductive cycle. The experimental diets were offered three weeks (21 days) after mating.  

The treatments (n DM basis) were:

• TF0 : Taro foliage silage 0% and rice bran 98.5%
• TF15 : Taro foliage silage 15% and rice bran 83.5%
• TF30 : Taro foliage silage 30% and rice bran 68.5%
• TF45 : Taro foliage silage 45% and rice bran 53.5%
• TF60 : Taro foliage silage 60% and rice bran 38.5%

Feeds, feeding and management

Taro foliage was harvested from natural ponds in the area. It was chopped (2-3cm) by hand and dried for one to two days to reducedthe moiture and then ensiled without additives. It was stored for one month before being fed. Rice bran was purchased from the local rice mill sconidered to be of low quality); calcium carbonate and salt were purchased from an animal feed shop in Phnom Penh. Diets were offered  at 2% of live weight (DM basis) during pregnancy and ad libitum during lactation. The rice bran and minerals were mixed together and fed first prior to feeding taro foliage silage.

Data collection

The gilts were weighed at intervals of 2 weeks during pregnancy and farrowing until the end of lactation which was for 42 days). The piglets were weighed at birth and then every week until weaning at 42 days. Feed intake was recorded during the gestation and lactation periods. Litter size at birth, birth weight, weaning weight, mortality (at birth and weaning), and live weight changes of the gilts during lactation were calculated.

Feed analysis

Taro foliage silage, rice bran, limestone and salt were analyzed for DM by oven drying at 60C for 48h. Nitrogen (N) was determined according to AOAC (1990).

Statistical analysis

Analysis of variance was performed using the general linear models of Minitab software (Minitab release 16.1.1, 2010). Sources of variation were treatments and error. When the F-test was significant at P<0.05, pair wise comparisons were performed using Turkey’s procedure (Minitab Statistical Software). The model used was:

Y_ij = μ + T_i + e_ij

Where, Yij = Dependent variables

μ = overall mean

T_i = treatment effect (i=1-2)

e_ij = random error

Linear and curvilinear regressions were calculated using Microsoft Office-Excel software.

Results and discussion

Chemical composition of ingredients

The  crude protein in taro foliage silage was slightly higher than we have reported previously (eg: 17%; Chhay Ty et al 2014) and confirms its value as a protein-rice supplement to be fed along with rice bran.

Feed intake

There were  curviline responses in intake of DM and crude protein during gestation and lactation with the maximum values recorded with 30% taro foliage silage in the diet DM (Tables 3 and 4; Figures 1 and 2). 

Figure 1: Effect of replacing rice bran with ensiled taro foliage on DM intake during pregnancy	Figure 2: Effect of replacing rice bran with ensiled taro foliage on CP intake during pregnancy

Figure 3: Effect of replacing rice bran with ensiled taro foliage on DM intake during lactation	Figure 4: Effect of replacing rice bran with ensiled taro foliage on CP intake during lactation

Live weight changes in gestation

The live weight gain of the gilts during pregnancy showed a curvilinear response to level of taro silage with the optimum at 30% replacement of the rice bran by taro foliage silage and no further change with up to 60% replacememt (Table 5; Figures 5 and 7). Feed conversion ratio showed a positive linear  response to level of taro foliage silage (Figure 6).

Figure 5: Effect of replacing rice bran with ensiled taro foliage on weight cahnges during lactation	Figure 6: Effect of replacing rice bran with ensiled taro foliage on DM feed conversion during lactation

Figure 7: Effect on live weight change of the gilts during gestation with replacement of rice bran by ensiled taro foliage

Live weight change during lactation

Loss of live weight during lactation was reduced by replacement of rice bran with ensiled taro foliage, with optimum values at 45 and 60%  levels of ensiled taro foliage in the diet (Table 6; Figure 8).In part this benficial; effect of the taaro silage can be related to the increase in dietry protein supply (at the 45% substitution level the diet crude protein concentration had increased to 13% in DM compared with 10% in the diet of rice bran alone (Table 3)).  The studies of O'Grady et al (1985) and Noblet et al (1990) support the importance of dietary protein level during lactation. Revel et al (1998) reported that sows offered a high protein diet during lactation (19.0% CP and 15.6 MJ DE/kg) lost only 4.3 kg during the four weeks of lactation (0.15 kg live weight loss/day), while those offered a low protein diet (7.9% CP and 15.5 MJ DE/kg as fed) lost on average 30.8 kg during lactation (1.1 kg/day).

Figure 8: Live weight loss of sow during lactation period fed rice bran replaced by different levels of ensiled taro foliage

Piglet performance

The number of piglets born was lowest on the 100% rice bran diet and highest with 60% replacement by Taro silage (Table 7; Figure 9). The total litter weight at birth did not difffer among treatments as weights of the piglets reflected the size of the litter. Litter weights at weaning did not differ among treatments (Figure 10) implying that milk production was not affected by the diet composition. This implication is supported by the overall feed conversion (feed consumed during gestation and lactation per kg piglet weaned) which did not differ among  dietary treatments (Figure 11).  The feed conversion for the diets with 45 or 60% ensiled tara foliage was some 50% poorer than that reported by Duyet and Preston (2013) for Mong Cai sows fed diets in which rice bran was replaced gradually by an ensiled mixture of banana pseudo-stem and taro foliage (DM conversion per piglet weaned was from 4 to 5 kg feed DM per kg piglet weaned). The use of gilts in the present experiment compared with 3rd parity sows used by Duyet and Preston (2013) is one explanation for this difference; the other is the known  high fertility of the Mong Cai breed and its capacity to use forage-based diets (Duyet 2010; Duyet et al 2010; Duyet and Preston 2013).

Figure 9: Piglets born alive from gilts fed rice bran replaced by different levels of ensiled taro foliage	Figure 10: Litter weight at weaning from gilts fed rice bran replaced by different levels of ensiled taro foliage
Figure 11: Feed consumed by the gilt (pregnancy and lactation) per kg of piglet weaned

Conclusions

• Diets composed of approximately equal parts (DM basis) of ensiled taro foliage and rice bran supported satisfactory reproduction and lactation in crossbred gilts.

Acknowledgments

The authors would like to express their gratitude to:  the MEKARN project financed by SIDA; the Center for Livestock and Agriculture Development (CelAgrid), for providing resources for conducting this experiment; and the students of Royal University of Agriculture for assistance in implementing this experiment.

References

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Received 21 May 2013; Accepted 21 April 2014; Published 1 June 2014

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