Rice distillers’ byproduct and biochar as additives to a forage-based diet for native Moo Lath sows during pregnancy and lactation

Bounlerth Sivilai and T R Preston¹

Department of Livestock and Fisheries, Faculty of Agriculture, National University of Laos, Vientiane Capital, Lao PDR
lerth_si@yahoo.com
¹ Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria (CIPAV), Carrera 25 No 6-62 Cali, Colombia

Abstract

Supplements of 4% rice distiller byproduct or 1% biochar had no effect on the feed intake and live weight change of Native Moo Lath sows fed a 70% forage diet during pregnancy and lactation. The litters of piglets from supplemented sows were 39% heavier at birth and 33% heavier at weaning than piglets from sows that were not supplemented. The overall feed conversion (feed consumed by the sows during pregnancy and lactation per unit weight of piglets produced at weaning) was improved by 25% by either of the supplement fed separately. There was less benefit when the sows were given both supplements.

Keywords: feed conversion, growth rate, piglets, prebiotics, probiotics, taro, weaning

Introduction

In order to improve the negative environmental image projected by most livestock production strategies the first step must be to reduce the dependence on imported cereal grains and soybeans the production of which in exporting countries is a major cause of deforestation, soil deterioration and loss of biodiversity. Such a strategy requires making better use of local feed and animal resources in the importing countries. Emphasis should be on crops that have a high potential for biomass production leading to high rates of extraction of carbon dioxide from the atmosphere and finally the sequestration of carbon to the soil.

The research described in this paper is part of an overall strategy that aims to make better use of local breeds and local feed resources for the benefit of small-scale farmers in rural areas.

Previous research (Sivilai et al 2018a) showed that native Moo Lath gilts gained more body weight during gestation, and were heavier at the end of lactation, when their forage-based diet was supplemented with 4% rice distillers’ byproduct (RDB). The litters from RDB-supplemented gilts were heavier at birth, and at weaning, than litters from un- supplemented gilts. Supplementation of the dams appeared to have no effect on piglet mortality at birth or during lactation. However, DM feed conversion, expressed as (total feed DM consumed during pregnancy and lactation/weight of piglets weaned), was improved by 60% when the Moo Lath gilts were supplemented with 4% RDB.

Beneficial effects on performance have been recorded when RDB was fed as a supplement in diets of growing pigs (Sivilai and Preston 2017), cattle (Sengsouly and Preston 2016; Sagkhom et al 2017) and goats (Silivong and Preston 2016). It is believed that these beneficial effects on animal performance arise from the action of a prebiotic in the form of β-glucan, present in the cell walls of cereal grains and yeasts, and released by the process of fermentation and distillation that occurs when rice is fermented and distilled to produce rice wine.

Biochar, the residue when fibrous waste is combusted at high temperature (500-1000 °C) in downdraft gasifiers (Rodriguez and Preston 2010; Orosco et al 2018) or updraft gasifier stoves (Philavong et al 2017) also appears to act as a prebiotic, in this case as a support mechanism for biofilms that facilitate the activities of beneficial microbial communities (Leng 2017). Positive effects of biochar supplementation on growth rate and feed conversion have been reported in cattle (Leng et al 2012; Sengsouly and Preston 2016) and goats (Silivong et al 2016: Phuong et al 2019; Thuy Hang et al 2019). Positive effects on growth and feed conversion of growing Moo Lath pigs when their forage-based diet was supplemented with either 4% of RDB or 1% of biochar were reported by Sivilai et al (2018b).

The objective of this research was to determine if there would be benefits on performance of Moo Lath sows from feeding biochar during the pregnancy – lactation cycle.

Materials and methods

Location

The experiment was conducted in the livestock farm of the Faculty of Agriculture, National University of Laos, Vientiane Capital, Lao PDR.

Sources of additives and forage preparation

The biochar was made from rice husk combusted in a gasifier stove (Philavong et al 2017). The rice distillers’ by-product was bought from traditional rice wine producers, mostly smallholder farmers, in the area surrounding Vientiane city. It was stored in closed containers to avoid contamination with moulds.

Taro (Colocasia esculenta) foliage (leaves + petioles) were collected from natural sources where waste water was stored; banana pseudo-stem was obtained from farmers with banana plantations. Taro foliage was processed by machine into particles of 0.5 to 1.0 cm. The inner part of the banana stem was chopped by hand into small pieces (1-2 cm). Both forages were wilted under shade for a day to reduce the moisture content to about 80%. They were then ensiled separately in anaerobic condition in closed plastic bags for 14 days prior to preparing the mixed diets (Table 1) and offering them to the sows.

Experimental design and treatments

The Moo Lath sows (n=12) were in their second reproduction cycle following the experiment described by Sivilai et al (2018a). The average live weight was 80.6 ± 9.3 kg. They were individually housed in concrete pens and fed a mixture of the ensiled forages supplemented with broken rice and soybean meal (Table 1).

The four treatments in a completely randomized design, replicated 3 times, were:

• CTL: no supplement
• RDB: rice distillers’ by-product at 4% of diet DM
• BIO: biochar at 1% of diet DM
• RDB-BIO: combination of RDB and BIO

Management

The sows were vaccinated against swine fever and dewormed with Ivermectin. They were mated with a native Moo Lath boar. The sows were fed 2% of live weight (DM basis) during pregnancy and ad libitum during lactation. Feeding times were 7:30 am and 4:30 pm. Water was freely available through nipple drinkers in the pens.

Data collection

Feed offered and refused was recorded every day during gestation and lactation. Samples of feeds offered and refused were taken at intervals and stored at -20°C until analysis.

The sows were weighed immediately after mating, prior to and after parturition, and at weaning. The litter size and individual piglet weights were recorded at birth and at weaning at 4 weeks. Mortality of piglets was recorded as it occurred.

Feed analysis

Dry matter (DM), crude protein (N*6.25), crude fiber (CF) and ash contents of feed ingredients were determined following AOAC (1990) procedures. pH of the silages was determined by electronic meter. Water retention of the biochar was determined by suspending 100 g of over-dry biochar in 1 liter of water and recording the weight of water absorbed after 24h.

Statistical analysis

The data were analyzed using the general linear model (GLM) of the ANOVA program in the Minitab (2016) software. Sources of variation were: treatments and error.

Results

Chemical composition and proximate analysis of diets

The biochar had a water retention capacity of 4.56 liters water/kg oven-dried biochar (Table 2), which is at the high end of the range of values reported for biochar produced from rice husks in a own-draft gasifier (Lanh et al 2019). Water retention capacity is considered to be indicative of the surface area of biochar and therefore its capacity to act as a support mechanism for biofilms that facilitate the activities of communities of micro-organisms (Leng 2017).

DM intake of sows during pregnancy and lactation

The feed intakes and the changes in live weight of the sows during pregnancy and lactation were not affected by supplementation with RDB or biochar given singly or in combination (Tables 3 and 4). By contrast the growth rates of the piglets from birth to weaning were increased both by biochar and RDB although these effects were less pronounced when both supplements were fed (Table 5; Figure 1).

The overall feed conversion of the system was calculated on the basis of total feed intake of the sows during pregnancy and lactation expressed in terms of the weight of the litters at weaning. (Table 5; Figure 2). On this basis both supplements improved the feed conversion ratio when given singly, although the effects where less marked when both supplements were fed.

Figure 1. Effect of RDB and biochar on litter weight of piglets at birth	Figure 2. Effect of RDB and biochar on litter weight of piglets at 28 days weaning
Figure 3. Effect of RDB and biochar on average daily gain of litters to weaning	Figure 4. DM feed conversion (total feed consumed in pregnancy-lactation/litter weight at weaning

Discussion

In a maize-growth “biotest” in a “grey” soil in Vietnam (Lanh et al 2019), rice husk biochar of the same water retention capacity, as that used in this experiment, supported a 25% increase in growth rate of maize compared with the zero biochar treatment. Rice husk biochar with a similar water retention capacity supported higher growth rates and reduced enteric methane in goats fed on cassava foliage (Thuy Hang et al 2019).

There were differences and similarities between the results of this experiment and the earlier one in which rice distillers’ byproduct and brewers’ grains were given as supplements to the same sows fed the same basal diet. In the previous experiment, the Moo Lath pigs were in their first gestation. In the present experiment the same sows were in their 2nd pregnancy. It may be that the lack of effects of the supplements on growth rates in the present experiment were because the sows had already reached maturity. By contrast he effects of the supplements on the weights and growth rates of the litters were similar between the earlier experiment and the present one. In both cases the overall feed conversion was improved by supplementation with RDB. The present experiment appears to have been the first attempt to feed biochar to indigenous sows throughout the whole reproductive cycle. The significance of the high percentage of the diets as forage (60% of diet DM from ensiled taro leaves and petioles and 10% from banana pseudo-stem), and the major response to both rice distillers’ byproduct and biochar fed separately, merits further study.

This experiment was concerned with potential economic responses to supplementation of native pigs with locally available feed resources. Understanding the mode of action of both rice distillers’ byproducts and of biochar is a separate issue. It is unlikely there were any viable microorganisms remaining in the rice distillers’ byproduct after the distillation, thus it cannot be categorized as a “prebiotic”. Biochar, the product of pyrolysis at temperatures exceeding 700⁰C, was essentially sterile. It is proposed that both these supplements can be considered as having effects on animal performance characteristic of “prebiotics” . It is thought that rice distillers’ solubles exert their effects though the presence of β-glucan, a valuable nutrient for microorganisms, liberated from the cell walls of rice during the process of fermentation and subsequent acid hydrolysis as the rice “wine” is distilled. For biochar, the proposal that it contributes “habitat”, enhancing activity of beneficial micro-organisms or sequestering those that are deleterious, such as mycotoxins, is an interesting hypothesis (Leng 2017), that is beyond the scope of our laboratory to investigate.

Conclusions

• Supplements of 4% rice distillers’ byproduct or 1% biochar had no effect on the feed intake and live weight change of Native Moo Lath sows fed a 70% forage diet during pregnancy and lactation.
  
  
• The litters of piglets from supplemented sows were 39% heavier at birth and 33% heavier at weaning than piglets from sows that were not supplemented.
  
  
• The overall feed conversion (feed consumed by the sows during pregnancy and lactation per unit weight of piglets produced at weaning) was improved by 25% by either of the supplement fed separately.
  
  
• There were no benefits when both supplements were fed

Acknowledgements

The authors would like to acknowledge  the MEKARN II project (Improving Livelihood and Food Security of the people in Lower Mekong Basin through Climate Change Mitigation), financed by Sida and co-research fund from National University of Laos (NUoL). Grateful thanks to the Faculty of Agriculture (NUoL) for providing the facilities to carry out this research.

References

AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. Washington DC

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Leng R A 2017 Biofilm compartmentalisation of the rumen microbiome: modification of fermentation and degradation of dietary toxins. Animal Production Science 57(11) 2188-2203 https://doi.org/10.1071/AN17382

Leng R A, Preston T R and Inthapanya S 2012 Biochar reduces enteric methane and improves growth and feed conversion in local “Yellow” cattle fed cassava root chips and fresh cassava foliage. Livestock Research for Rural Development. Volume 24, Article #199. http://www.lrrd.org/lrrd24/11/leng24199.htm

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Phuong L T B, Preston T R, Van N H and Dung D V 2019 Effect of additives (brewer’s grains and biochar) and cassava variety (sweet versus bitter) on nitrogen retention, thiocyanate excretion and methane production by Bach Thao goats. Livestock Research for Rural Development. Volume 31, Article #1. http://www.lrrd.org/lrrd31/1/phuong31001.html

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Sangkhom I, Preston T R, Leng R A, Ngoan L D and Phung L D 2017 Rice distillers’ byproduct improved growth performance and reduced enteric methane from “Yellow” cattle fed a fattening diet based on cassava root and foliage (Manihot esculenta Cranz). Livestock Research for Rural Development. Volume 29, Article #131. http://www.lrrd.org/lrrd29/7/sang29131.html

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Silivong P and Preston T R 2016 Supplements of water spinach (Ipomoea aquatica) and biochar improved feed intake, digestibility, N retention and growth performance of goats fed foliage of Bauhinia acuminata as the basal diet. Livestock Research for Rural Development. Volume 28, Article #98. http://www.lrrd.org/lrrd28/5/sili28098.html

Sivilai B and Preston T R 2017 A low concentration of rice distillers’ byproduct, or of brewers’ grains, increased diet digestibility and nitrogen retention in native Moo Lath pigs fed ensiled banana pseudo-stem (Musa spp) and ensiled taro foliage ( Colocasia esculenta). Livestock Research for Rural Development. Volume 29, Article #123. http://www.lrrd.org/lrrd29/6/lert29123.html

Sivilai B, Preston T R, Hang D T and Linh N Q 2018a Effect of a 4% dietary concentration of rice distillers’ byproduct, or of brewers' grains, on growth rate and feed conversion during pregnancy and lactation of native Moo Lath gilts and their progeny. Livestock Research for Rural Development. Volume 30, Article #20 http://www.lrrd.org/lrrd30/1/lert30020.html

Sivilai B, Preston T R, Leng R A, Hang D T and Linh N Q 2018b Rice distillers’ byproduct and biochar as additives to a forage-based diet for growing Moo Lath pigs; effects on growth and feed conversion. Livestock Research for Rural Development. Volume 30, Article #111. http://www.lrrd.org/lrrd30/6/lert30111.html

Thuy Hang L T, Preston T R, Ba N X and Dung D V 2019 Effect of biochar on growth and methane emissions of goats fed fresh cassava foliage. Livestock Research for Rural Development. Volume 31, Article #67. http://www.lrrd.org/lrrd31/5/thuyhang31067.html

Received 3 August 2019; Accepted 30 August 2019; Published 2 October 2019

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