This thesis will be defended at the Board of Examiners of Hue University, 04 Le Loi St. Hue city, ……..
This thesis can be found at: - University of Agriculture and Forestry, Hue University - National Library - Online webpage: www.hueuni.edu.vn
1 1. STRUCTURE OF THE THESIS This thesis consists of 101 pages comprising of 5 chapters, 38 tables and 34 figures. An introduction (3 pages), objective, hypothesis and innovation of thesis (5 pages); Chapter 1 (literature reviews): 25 pages, Chapter 2 (paper 1): 8 pages, Chapter 3 (paper 2): 11 pages, Chapter 4 (paper 3): 11 pages, Chapter 5 (paper 4): 9 pages, and general discussion, conclusion, implication, further research and reference and list of published scientific paper: 8 pages. In the table of content: chapter 1: 11 tables and 6 figures, chapter 2: 4 tables and 5 figures, chapter 3: 5 tables and 10 figures, chapter 4: 9 tables and 10 figures, chapter 5: 3 tables and 4 figures and list of abbreviation (1 page). 2. INTRODUCTION Approximately 75% of production is produced in tradition by rural pig farmers (Souriyasack, 2011). The typical smallholder pig farm relies on a scavenging system for forages and left-over food with little or no supplementation. The results are low productivity (Stür et al., 2010) with growth rates often less than 100 g/day (Phengsavanh et al., 2010) and low reproductive performance of sows is marked by depressed litter size, a high mortality of piglet and outbreaks of disease. For these reasons the
two feed resources chosen for this research were banana pseudo stem as source of energy and the Taro plant as the source of protein. Banana pseudo stems (BPS) from the banana tree are distributed in Laos, farmers chopped it into small pieces and fed to pigs, ducks and chickens (Tien et al., 2013). The fibre is presented in BPS, a high content of water 94%, low level of protein 3-4% in DM (Floulkes et al.,1978). However, an unusual finding was reported presence of 3% of soluble sugars in the
2 liquid fraction, it confirms that they are readily fermentable (Dao Thi My Tien et al., 2010). Taro leaves are rich in protein (about 20% in DM) with a balance of essential amino acid close to that in an “ideal” protein (Rodríguez et al., 2006). The petioles are rich in sugars which facilitate ensiling the combined leaves and petioles to give a feed with 14-15% CP in the DM (Malavanh et al., 2008; Giang et al., 2010; Hai et al., 2013). Many experiments have demonstrated that ensiled taro foliage can be fed as a source of protein for pigs (Toan and Preston, 2010; Chittavong et al., 2012; Kaensombath and Lindberg, 2012; Hang et al., 2015). The limitation to the use of taro foliage in diets for pigs is the presence of oxalates which form crystalline insoluble salts that cause irritation in the mouth of pigs when the foliage is consumed fresh. However, this problem can be resolved by ensiling the taro before feeding (Hang et al., 2011). Brewers’ spent grains’ and rice distiller soluble fed at low levels in the diet (4 to 5% as DM) were shown to protect cattle (Phanthavong et al., 2016; Sengsouly and Preston 2016; Binh et al., 2017) and goats (Binh et al., 2018) from HCN toxicity caused by cyanogenic glucosides present in foliage of “bitter” varieties of cassava. However, no any applied in pig with use these byproducts. Its’ properties are acting probiotics/prebiotics to replace antibiotics with either beneficial microorganisms such as Lactobacilli and yeasts that enhance the normal microbial flora in the animals’ digestive system. In the latter category are compounds such as β-glucan that are present in the walls of cereals such as barley and rice, and of yeasts. These appear to be released in natural processes such as occur in the alcoholic fermentation with distillation to give beer and rice wine.
3 Biochar, the by-product from the carbonization of fibrous residues at high temperatures of 500-1000 °C was originally identified as an ameliorating agent in soils and as a vehicle for sequestering atmospheric carbon (Lehmann, 2007) with associated beneficial effects on crop and plant growth (Lehman and Joseph, 2015; Preston, 2015). In pigs and chickens, it has been shown to be effective as an agent to facilitate the degradation of phytotoxins and mycotoxins (Gallo et al., 2015; Prasai et al. 2017), as well as providing habitat that enhances activities of microbial communities (Leng, 2017). 3. OBJECTIVES OF THE THESIS 1) To determine the effect of replacing ensiled taro foliage with ensiled banana pseudo stem as foliage based die for Moo Lath pigs in Laos 2) To investigate the effect of a low concentration of rice distillers’ byproduct or brewers’ grains as additive feed in the foliage based diet for Moo Lath pigs 3) To evaluate the effect of rice distillers’ byproduct and biochar as additives on growing and feed conversion of native Moo Lath pigs in Laos 4. HYPOTHESES OF THE RESEARCH 1) Ensiled taro foliage combined with ensiled banana pseudo stem will be contributed suitable inclusive level as foliage baseddiet supporting for digestibility and improving growing for Moo Lath pigs 2) Small amounts (4% of diet DM) of either brewers' grains or rice distillers' byproduct (Quilao) supplemented in foliage based diets would support increased growth rate and reproductive performance in Moo Lath pigs.
4 3) Supplementation of biochar in a forage-based diet would be affected on growth performance and feed conversion of native Moo Lath pigs 5. INNOVATION OF THE DISSERTATION The innovation of this dissertation is the use of low concentrations (4% of diet DM) of agro-industrial by-products such as brewers’ grains, rice distillers’ residues and addition of biochar (1% of diet DM) as additives feed that appear to act as “prebiotics”, enhancing the growth and feed conversion of indigenous Moo Lath pigs fed on local feed resource of ensiled foliage of Taro (Colocasia esculenta) and banana pseudo-stem (Musa spp). CHAPTER 1 LITERATURE REVIEW 1.1. The role of pig production Smallholder farms are practice accounted for 86.5% of total pig production in 2017 (MAF, 2017). Around 64% of pig rising is for home consumption especially in cultural events, accumulation capital and generated cash income (Stür et al., 2002). Souriyasack (2011) implied that approximately 75 % of pigs are produced in small-scale systems and 25% is derived from commercial farms. There are total number of pigs of 3.7 million heads in whole country, with local pigs are accounted of 3.2 million pigs (DLF, 2017). Meat required to consume for Lao people is 57 kg/capita, with pork are 14.6 kg in 2017 1.2. Currently typical pig farming in Laos Pig rearing system in Laos can be clarified into three main categories such as smallholder pig production (small scale), semiintensive (medium scale) and commercial scale (large scale) farming. Smallholder pig farms are approximated of 86.5% of pig
5 production (MAF, 2017). In this system, pig farmers are poor addition feeds for pigs, with no protected from disease, with poor nutrients. Semi-intensive pig farming is defined as small family business farming system by raise pig including indigenous pig and cross breed pig. It can definite relatively high level of inputs. The commercial pig farms in Laos are arisen as enterprise sectors under domestic investors and the typical commercial pig farms. Mostly pigs used are exotic breeds such as crossed breed of Large White, Landrace, Duroc Jersey and some of hybrid (Wilson, 2007). 1.3. Feeds and feeding practical management Feeds derived from agricultural by-products mainly rice bran, broken rice, polished rice and also maize and cassava root are a source of energy diet for pigs. The green plants are taro foliage, banana pseudo stem, thick head, paper mulberry and green amaranth, and vegetarians such as pumpkin tops and sweet potato leaves. Feeds derived from leftover materials rice distillers’ waste and household scraps are traditional knowledge to use as feed for pigs 1.4. Utilization of forage-based diet for pigs 1.4.1. Taro as protein sources for pigs Taro (Colocasia esculenta) is traditionally forage that cultivated by farmers, it also arises naturally in Laos. It is contained a high potential source of protein in pig diets. Taro is sources of amino acid closed to ideal protein with similar contents compare to soybean meal (Rodríguez et al., 2006). Use of taro was increased in CP digestibility and N retention (Rodríguez et al., 2009). Ensiled taro leaves could be replaced up to 50 % of the soybean protein by improving growth performance and carcass traits of crossbred large white pig and native Moo Lath Lao pigs (Kaensombath and Erik Lindberg, 2012).
6 1.4.2. Banana pseudo stem in pig diets A mixture of ensiled banana pseudo stem and taro foliage has been contributed to improve intake for native Moo Lath pig (Manivanh and Preston, 2016). The researchers subjected to use banana pseudo stem combining to taro leave and also replacing with rice bran in traditionally performance by farmers for crossbreed pig and Mong Cai sows (Hang et al., 2014; Duyet et al., 2013), duck diets (Dao Thi My Tien et al., 2013) and pig diet (Chhay Ty et al., 2014). However, high fiber content appeared to decreased digestibility of DM, OM, NDF and N retention when ensiled banana pseudo-stem replaced taro foliage silage in crossbreed pig (Hang et al., 2014). 1.4.3. Brewers’ grain and distillers’ by-product Rice distillers’ by-product (RDB) are the residue derived mainly from yeast fermentation process of rice of polished rice to make rice wine. Rural smallholder farmers have been successfully used RDB as a protein sources for pigs (Manh et al., 2009; Taysayavong and Preston, 2010; Manivanh et al., 2012; (Phiny et al., 2012). Brewers’ grains and rice distiller soluble fed at low levels in the diet (4 to 5% as DM) were shown to protect cattle (Phanthavong et al., 2016; Sengsouly and Preston 2016; Binh et al., 2017) and goats (Binh et al., 2018) from HCN toxicity caused by cyanogenic glucosides present in foliage of “bitter” varieties of cassava. However, no any applied in pig with use these byproducts. 1.4.4. Biochar as a feed additive in animals Primarily study with 1 % of biochar is applied on the growth and feed conversion including reduction methan emission in cattle (Leng et al., 2014; Sengsouly and Preston, 2016) and goats (Silivong et al., 2016; Le Thi Thuy Hang et a., 2018). The benefit of biochar is possibility bind toxins or degraded some
7 organisms in the gut of animal microbiome (Leng, 2017). Prasai et al. (2016) that supplementation of biochar improved egg yield and feed conversion. whilst, supplementation of 1 % rice husk biochar in chicken diet reduced coliform bacteria and E-coli in faces, but had no impact on live weight gain (Hien et al., 2018). CHAPTER 2 EFFECT OF REPLACING ENSILED TARO FOLIAGE WITH ENSILED BANANA PSEUDO STEM ON INTAKE, DIGESTIBILITY AND NITROGEN RETENTION IN MOO LATH PIGS Introduction Banana pseudo stem is traditionally and commonly used by farmers as feed for pigs, and cattle in Laos. This research aimed to test the effect of different proportion of ensiled banana pseudo-stem combined with ensiled taro foliage on intake, digestibility and nitrogen retention in growing Moo Lath pigs. Materials and Methods Treatment, experimental design and feeding management Four native Moo Lath pigs (LW at 30 kg 2.63 kg) were used with arranged in a 4x4 LSD with 4 pigs and 4 levels of ensiled banana pseudo stem (0, 5, 10 and 15% in DM basis) replacing ensiled taro foliage. Experimental periods lasted 10 days: 5 days for adaptation and 5 days for collection of urine and feces. Sample collection and analysis Feeds offered and refused were weighed daily. The urine and feces were collected. All samples were analysed for DM, CP, CF and ash. The data were analyzed (Minitab, 2016).
8 Results and discusion Feed intake and apparent digestibility Feed intake, coefficients of digestibility, daily N retention, and N retention as proportion of N digested, all declined linearly as the proportion of ensiled banana pseudo-stem in the diet was increased with the trend being more pronounced in the case of crude fiber. However, the data on N retention show clearly that the protein provided by ensiled taro foliage was superior biological value compared with the combination of banana pseudo-stem Table 2.3. Intake and apparent digestibility of diets Diets, % DM basis BS0 BS5 BS10 BS15 Feed intake, g/d 921. 910. DM 917.6 914.9 2 1 Apparent digestibility, % DM 88.5a 84.9ab 83.6b 83.6b CP 84.9a 80.7ab 80.3ab 77.2b CF 81.6a 74.9ab 71.6b 68.6b OM 88.9a 85.6ab 84.1b 83.6b N balance, g/d Intake 25.3a 24.7ab 24.1b 23.9b b ab ab Feces 3.8 4.8 4.8 5.4a c bc ab Urine 5.5 6.9 7.9 8.8a N retention g/d 16.0a 13.0b 11.5bc 9.7c a b bc % of N intake 63.1 52.7 47.4 40.6c % of digested N 74.0a 65.4ab 59.2bc 51.7c (BV)
1.06 1.38 2.00 1.04
0.004 0.002 <0.001 0.002
0.31 0.32 0.39
0.013 0.008 <0.001
9 Conclusion Apparent digestibility of DM and CP, daily N retention and N retained as percent of N digested, all declined linearly as ensiled banana pseudo-stem replaced ensiled taro foliage. It is apparent that the biological value of the protein in the ensiled taro foliage is superior to that in the combination of ensiled banana pseudo-stem and soybean meal CHAPTER 3 A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT OR BREWERS’ GRAINS ON DIGESTIBILITY AND NITROGEN RETENTION IN NATIVE MOO LATH PIGS Introduction Brewers' grains have been widely used as protein supplements in diets of pigs and cattle. However, recent research Binh et al. (2017) suggests that they may also provide other benefits, as a source of "prebiotics". The hypothesis that small amounts (4% of diet DM) of either brewers' grains or rice distillers' byproduct would support increased growth rate in local Moo Lath pigs. Materials and methods Treatments, design and Feeding management Six pigs (native Moo Lath pig breed) with average initial live weight of 29.3 2.3 kg with 3 diets: CTL; BG 4% and RDB 4%. A double 3*3 LSD with periods of 10 days: 5 days for adaptation and 5 days for measurement of data Data collection and analysis Feed offered and refused, Urine and feces were recorded daily. The samples were analysed for DM, N, CF and ash (AOAC, 1990). The data were analysed (Minitab, 2014).
10 Results Feed intake DM intake was increased respectively by inclusion of BG and RDB in the diets. Table 3.3. Mean values for DM intake and % CP of the diet consumed by Moo Lath pigs Diets, as % DM basis SEM p CTL BG4% RDB4% Feed intake, g/d DM intake 703b 777a 805a 13.38 <0.001 CP intake 90.3b 101.2a 104.5a 1.73 <0.001 CF intake 127.2b 138.2a 143.0a 2.87 0.001 OM intake 86.2a 84.3b 82.5c 0.53 <0.001 c b DM intake, g/kg LW 21.5 25.5 27.8a 0.53 <0.001 ab
Mean values within rows with different superscript differ at P<0. 05
Apparent digestibility Apparent digestibility for DM, OM, CF and CP were increased by both supplements. Table 3.4. Mean values for apparent digestibility by Moo Lath pigs CTL BG4% RDB4% SEM p Apparent digestibility, % Dry matter 84.5b 87.5a 89.6a 0.84 <0.001 b ab a Crude protein 75.6 79.4 80.7 1.41 0.032 Crude fiber 79.5b 86.2a 88.7a 1.11 <0.001 b a a Organic matter 84.7 87.8 89.9 0.81 <0.001 ab
Mean values within rows with different superscript differ at P<0. 05
Nitrogen balance N intake and N retained was greater on the BG and RDB diets increases in DM intake induced by the supplements. There was no advantage from supplementation with BG. The biological value of the protein was increased by both BG and RDB Table 3.5. Mean values for N balance by Moo Lath pigs CTL BG 4 % RDB 4 % SEM
11 N balance, g / d Intake 14.5b 16.2a 16.7a 0.28 <0.001 Feces 3.2 3.4 2.9 0.19 0.23 Urine 2.2a 2.1a 1.5b 0.17 0.010 N retained g/day 9.00c 10.7b 12.3a 0.35 <0.001 b b g/day# 10.2 10.3 11.3a 0.27 <0.001 % of digested N 73.8b 83.1a 87.2a 1.91 <0.001 ab Mean values within rows with different superscript differ at P<0. 05
Discussion Previous research with BG (Amaefule et al., 2006) and RDB (Luu Huu Manh et al., 2003) have used as source of protein. As far as we are aware, this is the first report on the use of these supplements at low levels as source of prebiotics (Fuller, 1989; Vanbelle et al., 1990). It is suggested that presence in both the supplements of β-glucan, a carbohydrate component of the cell wall of cereal grains and fungi including yeasts. Conclusion BG and RDB, each at concentrations of 4% of diet DM, improved feed DM intake and apparent digestibility of DM, CP and CF. N retention was increased by RDB but not by BG and the biological value of the protein was increased by both supplements. It is suggested that the positive effects on pig performance, of both BG and RDB, may have been due to the presence of βglucan, a component of the cell wall of cereal grains and yeasts. CHAPTER 4 EFFECT OF A LOW CONCENTRATION OF RICE DISTILLERS’ BYPRODUCT OR BREWERS' GRAINS ON PREGNANCY AND LACTATION OF NATIVE MOO LATH GILTS AND THEIR PROGENY Introduction
12 In a previous experiment Silvai and Preston (2017) showed that BG and RDB, each at concentrations of 4% improved DM intake and digestibility in native Moo Lath pigs. The objective was to test if these supplements would bring about similar benefits during pregnancy and lactation in native Moo Lath gilts. Materials and methods Treatments and experimental design 12 Moo Lath gilts (BLW at 80.8± 3.9 kg) were fed ad libitum a basal diet of broken rice and ensiled BS with ensiled TF. The three treatments in a CRD with 4 replications were: No supplement (CTL); RDB 4% and BG 4% of diet DM Data collection and analysis Feed offered and refused was recorded. The gilts weight, litter size, piglet weights at birth and at weaning days, mortality of piglets and new estrus was recorded. Samples were analysed for DM, CP, CF and ash (AOAC, 1990), and all data were analysed (Minitab, 2016). Results Body weight change during pregnancy and lactation Moo Lath gilts gained more body weight during gestation, and were heavier at the end of lactation, when their diet was supplemented with 4% BG or 4% RDB. Table 4.3. Llive weight (kg) of Moo Lath gilts CTL
BG 4% RDB 4% SEM
Table 4.4. Changes in weight of Moo Lath gilts CTL BG 4% RDB 4% Changes in live weight, kg Conception to pre-parturition 17.2b 28.3a 29.2 a b a Post-parturition 10.9 20.9 20.8 a Parturition to weaning -25.5 -21.4 -21.2 Weight loss, % 24.6 22.4 21.5 Weaning to oestrus. Days 16.8 13.3 13.5
2.27 2.13 3.92 4.68 2.37
0.08 0.01 0.69 0.89 0.52
Piglet production Litters from Moo Lath gilts supplemented with 4% RDB were heavier at birth and at weaning, and tended to grow faster, than litters from un-supplemented gilts Table 4.5. Mean values for weight of litters from Moo Lath gilts CTL BG 4% RDB 4% SEM p Birth, kg 5.14a 6.39ab 7.65b 0.599 0.047 Weaning (at 28d, kg) 23.9a 29.5ab 39.1b 3.01 0.036 a ab ADG, g/d 683 855 1072b 130 0.061 ab Means without common superscript differ at p<0.05
Health and mortality Supplementing the Moo Lath gilts during pregnancy and lactation with BG or RDB had no effect on piglet mortality at birth or during lactation on piglet live weights at birth and 28 days weaning
Table 4.6. Numbers of piglets born and surviving to weaning CTL BG 4% RDB 4% Number born Total 8.25 8.5 9.25 Dead 0.50 0.00 0.00 Alive 7.75 8.50 9.25 Number weaned Alive 6.50 7.25 8.25
14 Died Mortality, % Total Lactation
Table 4.7. Mean weights (g) of piglets at birth and 28 day weaning
Feed conversion Supplementing of BG or RDB during pregnancy and lactation indicated different value on feed DM intake. DM feed conversion was improved by 60%, when supplemented 4% RDB Table 4.8. DM intake from conception to weaning of Moo Lath gilts CTL
Piglets weaned, kg
DM intake, kg/d
Means without common superscript differ at p<0. 05
Discussion The beneficial effects on accumulation of body mass of Moo Lath gilts during pregnancy and on the weight of their litters at weaning, as a result of supplementing their diet during pregnancy and lactation, with small quantities of rice distillers’ by-product, confirm our earlier findings of increased diet
15 digestibility and N retention in growing Moo Lath pig feeds fed the same basal diet and RDB supplement (Sivilai and Preston, 2017). The apparent superiority of rice distillers’ by-product over brewers’ grains was a common finding in both studies. These positive effects on growth rate and feed conversion are similar to what has been reported for rice distillers’ by-product in diets of cattle (Sangkhom et al., 2008; Sengsouly et al., 2016) and for brewers’ grains in diets of cattle (Phuong et al., 2017) and goats (Vor Sina et al., 2017). It is relevant to reflect on the mechanism by which rice distillers’ byproduct, and to a lesser extent, brewers’ grains, contribute to the observed improvements in performance of both ruminant and mono-gastric animals. We previously suggested (Sivilai and Preston, 2017) that the benefits of both brewers’ grains and rice distillers’ by-product, in supporting improved feed intake, digestibility and N retention in growing pigs, could be explained by the presence in both the supplements of β-glucan, a carbohydrate component of the cell wall of cereal grains and yeasts. The beneficial effect of β-glucan on growth rate and health in weaning pigs was recently reported by Nguyen Thi Thuy (2017). The immune-modulating effects of β-glucans, with beneficial health effects in humans and animals are well known (Novak and Vetvicka, 2008; Waszkiewicz-Robak, 2013). The question is: what is the mechanism that leads to rice distillers’ by-product and brewers’ grains being an active source of β-glucan? It is well understood that the carbohydrate complexes in the cell wall of cereal grains and yeast need to be modified in order to make available the beta-glucan and related compounds. Alkaline followed by acid hydrolysis appear to be the key steps in this process (Yanelys Garcia, Personal communication). In the
16 production of rice “wine” the procedure is first the steaming of the rice, followed by facultative anaerobic fermentation with yeast, and lastly the boiling of the fermented rice to release the alcohol. Similar procedures are followed in the production of beer and the resultant by-product of brewers’ grains. The first stage of “steaming” (rice wine) and “mashing” (beer) and the initial steps in the fermentation may facilitate the first requirement for alkaline hydrolysis; the last stage of distillation in which the fermented substrate is “acid” would appear to simulate the process of “acid hydrolysis”. The challenge is to simulate these actions using more readily available and lower cost carbohydrate substrates such as cassava root and cassava root pulp. Conclusions Moo Lath gilts gained weight during gestation, and lactation, when supplemented BG 4% or RDB 4%. The litters size and mortality of piglets supplemented with RDB were improved Weights of piglets at birth and 28 days weaning, and intake were not affected by supplementation but feed conversion was improved by 60%, when supplemented with RDB 4%.
17 CHAPTER 5 EFFECT OF RICE DISTILLERS’ BYPRODUCT AND BIOCHAR AS ADDITIVES FOR GROWING AND FEED CONVERSION OF NATIVE MOO LATH PIGS Introduction RDB fed in small quantities (4% of the diet) also acts as a prebiotic. It increased N retention in pigs (Sivilai and Preston, 2017) and improving growth and feed conversion in pregnantlactating gilts and growth rate of piglets to weaning (Sivilai et al., 2018). Feeding biochar to animals is a recent development. The objective was to evaluate the effect of biochar on the growth rates of Moo Lath pigs fed forage diet and to compare with RDB. Materials and Methods Animals, treatment, design and management Twenty Moo Lath pigs (15.8 ± 1.3 kg) were fed four dietary treatments arranged in a CRD with 5 replications: CTL, RDB 4%, BIO 1% and RDB+BIO added in the diets. Data collection and analysis The pigs were weighed every 14 days and feeds offered and refused were recorded daily with samples were determine for DM, CP, CF and ash (AOAC, 1990). The data were analyzed (Minitab, 2016). Results Dry matter intake, growth rate and feed conversion There was no effect of the additives on feed intake. Growth rate tended to be better and feed conversion was improved for both additives. There were no benefits from combining both additives compared with feeding each one separately.
18 Table 5.3. Mean values for change live weight, feed intake and conversion for Moo Lath pigs Live weight CTL BIO RDB BIO+RDB SEM Initial, kg 15.9 15.8 15.6 16.0 0.619 Final, kg 36.5 40.5 40.1 41.6 1.52 Daily gain, g 179 215 220 220 9.51 DM intake, g/d 787 850 859 874 41.7 DM conversion (kg/kg) 4.43b 3.96a 3.89 a 4.02 a 0.13 ab
p 0.692 0.423 0.089 0.58 0.048
Means without common superscript are different at p<0.05
Discussion The positive effect of RDB on growth rates and feed conversion of the Moo Lath pigs agrees with previous results where: RDB 4% improved N retention by 36% and the biological value of the nitrogen by 18% (Sivilai and Preston, 2017) and RDB4% increased the litter weight of weaned pigs by 67% and the overall feed conversion by 64% (Sivilai et al., 2018). To our knowledge, the feeding of biochar to pigs has not previously been reported. The degree of response observed in this experiment with growing pigs (20-23% and 11-14% for growth and feed conversion) is similar to the 15 and 18% improvements in growth and feed conversion reported for biochar fed to cattle (Sengsouly and Preston, 2016). Biochar and RDB each increase pig growth rate and efficiency but they were effected when they combined. Conclusions In pigs, growth rate tended to be better (p=0.089) and feed conversion was improved (p=0.048) for both additives, fed separately or together, when compared with the control diet. There were no benefits from combining both additives It is postulated that biochar and distillers’ byproduct recommended to bind toxins from the feed which are either
19 excreted in the feces or degraded by some organisms in the animal’s gut microbiome. GENERAL DISCUSSIONS AND CONCLUSIONS The reasons for using indigenous pig breeds such as the Moo Lath in rural areas of Laos, usually in some form of semiscavenging system have been well documented (Phengsavanh et al., 2011). Bananas are grown everywhere in Laos and there is a long tradition of chopping the pseudo-stem and feeding it to pigs and poultry. However, this abundant feed resource has received little attention from researchers. By contrast, Taro have been thoroughly researched as a component of diets for pigs (Chittavong et al., 2012; Kaensombath and Lindberg, 2012; Hang et al., 2015). The only negative attribute the high level of oxalic acid has been shown to be controllable by ensiling and supplementation with a source of calcium (Hang et al., 2011). The objective of this thesis was to test a number of initiatives which would lead to better utilization of these two forages abundantly available in tropical ecosystems when fed to indigenous native “Moo Lath” pigs. In Paper 1 (chapter 2), the experimental diets were (% DM basis) ensiled banana pseudo-stem: 0, 5, 10 and 15% the results were supported evidence for the decision made in the conclusion to restrict the level of ensiled banana pseudo-stem to 10%. In Paper 2 (chapter 3) was a follow-up to findings by fellow researchers (Phanthavong et al., 2016; Sangkhom et al., 2017; Binh et al., 2017; Sengsouly et al., 2016) that byproducts of beer manufacture (brewers’ grains) and local rice wine fermentation-distillation. It was suggested beneficial presence of β-glucan, a component of the cell wall of both cereal grains and
20 yeasts, that is unknown for RDB and BG in pig diet, as this result is positive effect on digestibility and N retention The follow-up to the previous experiment in paper 3 (chapter 4) was the testing of the same two additives in the diets of pregnant and lactating native Moo Lath gilts and their progeny to weaning. The gilts gained more body weight during gestation, and were heavier at the end of lactation, when their diet was supplemented with 4% BG or 4% RDB. Litters from dams supplemented with the additives were heavier at birth, and at weaning, and grew faster than litters from un-supplemented gilts. Supplementation of the dams appeared to have no effect on piglet mortality at birth or during lactation, nor on live weights of piglets at birth or weaning, and did not affect overall feed DM intake. However, DM feed conversion was improved by 60% when the Moo Lath gilts were supplemented with 4% RDB The experiment described in Paper 4 (chapter 5) was also a follow-up to findings by colleagues (Leng et al., 2012; Silivong and Preston, 2016; Sengsouly and Preston, 2016) that biochar appeared to have “prebiotic” properties when fed to cattle and goats. Biochar was fed at 1% of the basal diet of taro-banana pseudo stem in a comparison with RDB at 4%. Growth rate tended to be better (p=0.089) and feed conversion was improved (p=0.048) for both additives, fed separately or together, when compared with the control diet. There were no benefits from combining both additives compared with feeding each one separately. Whilst considerable research needs to be done, the possibility is that biochar and RDB bind toxins or immobilize anti-nutritional compounds in feeds which are either excreted in the feces or degraded by some organisms in the animal’s gut microbiome, thesis concluded:
21 1) The biological value of the protein in ensiled taro foliage was not recommended to have more than 10-15% of ensiled banana pseudo-stem in a diet based in ensiled taro foliage for native Moo Lath pigs. 2) Additives (4% in diet DM) in the form of rice distillers’ byproduct or brewers’ grains, improved feed intake, digestibility and N retention, with a greater response in N retention and biological value of the protein for rice distillers’ byproduct. 3) These additives also improved performance of gilts when fed throughout pregnancy and lactation with specific benefits in weight of piglets weaned and overall feed conversion. 4) Biochar fed at 1% of diet DM, appeared to support equal benefits in growth and feed conversion in Moo Lath pigs as the 4% addition of rice distillers’ byproduct. It is suggested that both these additives act as “prebiotics” in neutralizing anti-nutritional components in the feed thus enhancing animal performance and wellbeing.
LIST OF PUBLISHED SCIENTIFIC PAPERS Sivilai, B., Preston, T.R. and Kaensombath, L., 2016. Feed intake, nutrient digestibility and nitrogen retention by Moo Lath pigs fed ensiled banana pseudo-stem (Musa spp) and ensiled taro foliage (Colocasia esculenta). Livestock Research for Rural Development, 28 (6), http://www.lrrd.org/lrrd28/1/boun28006.html Sivilai, B. and Preston, T.R., 2017. Effect of level of dietary protein on growth and feed conversion of Moo Lath pigs fed a mixture of ensiled taro foliage (Colocasia esculenta) and of ensiled banana pseudo-stem (Musa spp). Livestock Research for Rural Development, 29 (34). http://www.lrrd.org/lrrd29/2/boun29034.htm 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. 29 (123). http://www.lrrd.org/lrrd29/6/lert29123.html Sivilai, B. Preston, T.R., Hang, D.T. and Linh, N.Q., 2018. 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, 30 (20). http://www.lrrd.org/lrrd30/1/lert30020.html Sivilai, B., Preston, T.R., Leng, R.A., Hang, D.T. and Linh, N.Q., 2018. Rice distillers’ byproduct and biochar as additives to a forage-based diet for growing Moo Lath pigs; effects on growth and feed conversion. Livestock