Composition and nutritive value of rice distillers’ by-product (hem) for small-holder pig production

 

Luu Huu Manh, Tran Chi Binh, Nguyen Nhut Xuan Dung
and Bui Phan Thu Hang

 

Cantho University, Cantho, Vietnam

 

Abstract

A survey of 40 families producing pigs in the Mekong delta showed  that farmers who used  “hem“ (rice distillers’ by-product)  fed much less purchased concentrates (usually none) and had greater economic benefits, even though the performance traits of their pigs were lower, than in the case of producers who did not use “hem” but fed higher levels of concentrates. Analysis of samples of "hem" showed that the protein content ranged from 17 to 33% (mean of 23%) in dry matter and that it had a well-balanced array of amino acids.

 

Key words: Pigs, rice distilling residue, by-product, protein, amino acids

 

Introduction

In recent years pig production in the Mekong delta has been decreasing because of the imbalance between feed and animal product prices, which has resulted in lower economic returns for small farmers. Many feed factories offer concentrates for pig producers not only in the towns, but even in the remote rural areas. This has contributed to the development of feeding systems that are expensive, and not based on locally available and cheap feed resources. Rice distillers’ by-product (“hem”) is the waste derived from artisan production of alcohol from rice. The rice is cooked and yeast is added to the cooked rice for the fermentation. The alcohol is distilled from the fermented liquor, after which the waste “hem” is used as wet feed for pigs.

 

Rice distillers’ by product is produced in large amounts in some places in the Mekong delta, such as Chau Thanh, in Long My district. This by-product is cheap and available the whole year round. “Hem” is very palatable, and using it in diets for fattening pigs is a way for the farmer to get good economic returns.

 

A survey was conducted in Long My district to compare the situation of pig farmers that use, and those that do not use, “hem”. Samples of “hem” were collected for analysis of the nutrient composition, especially the amino acids.

  

Materials and methods

Location

The survey was conducted on 40 selected families in 6 hamlets located in Long My district. These families were divided into 4 groups, each group consisting of 10 families:

·        Group A: Use “hem” to feed sows

·        Group B: Do not use “hem” to feed sows

·        Group C: Use “hem” to feed fattening pigs

·        Group D: Do not use “hem” to feed fattening pigs

 

Data collection methodology

Interviews:

Discussions were held on farms producing “hem” and with pig producers, and focused on:

• General information on “hem” production
• “Hem” output capacity per day

·        “Hem” yield  obtained

·        The use of “hem”, for example with other feeds and concentrates

·        Evaluation of the performance of pigs, with or without hem in their diets

·        Assessment of the opportunities and potential of  “hem” in pig production.

 

 Sample collection:

A total of 18 “hem” samples were collected. These samples were analysed for dry matter (DM), crude protein (CP), crude fibre (CF), ether extract (EE), ash, neutral detergent fibre (NDF), calcium (Ca), phosphorus (P) and gross energy (GE), and amino acid content. Forty feed samples from producers who used and did not use “hem” were taken to evaluate the diets fed.

 

Results and discussion

Chemical composition

Most of the “hem” samples had very low DM content, with considerable variation because some samples (such as samples 4, 10 and 12) were diluted before collection (Tables 1 and 2). The CP and GE values were rather high, varying from 17 - 32% and from 18 – 21 MJ/kg DM, respectively. These values can be compared with the CP and GE contents of hull-less rice, 8% and 15 MJ/kg DM, respectively (Nguyen Nhut Xuan Dung et al 1997).  Fibre levels (8.4 - 24.2% NDF in DM) were found to be quite variable depending on the rice used in the fermentation. Ca and P contents in DM were found to be rather low, ranging from 0.31 - 0.87% and 0.17- 0.5%, respectively. Most of the yeast used to produce the alcohol was produced locally at artisan level. This, and the fact that the composition of distillers feeds is influenced by the raw materials used, as well as processing procedure and the type of equipment used in distillation (Carpenter 1970) resulted in the chemical composition of  the “hem” being very variable. Average pH was 3.2, and at this value “hem” can be stored in a jar for up to 3 days. However, due to the low pH value,  pig producers often add water before feeding. The quality of the protein in “hem” is quite good; mean lysine content was found to be 3.9 g/16g N, although cystine and methionine concentrations were rather low.

 

 

 

 

 

Farms with sows that used or did not use “hem”

Farms that used “hem” in sow diets:

“Hem” was substituted at levels ranging from 11 to 57% in diets based on rice bran. The chemical composition of the sow diets varied, especially the dry matter content, which was rather low and ranged from 5 to 18%.  When “hem” was used, concentrate was rarely provided (Table 3).  Producers that used  “hem “ had fewer sows (mean 1.7) compared to those who did not feed “hem” (mean 3.7) (Table 5).  

 

 

Farms that did not use “hem” in sow diets:

Rice bran is usually the main energy source used for pigs in the Mekong Delta. When “hem” was not included in sow diets, approximately 70% of the farmers supplied concentrate for their sows, with the result that average crude protein content was improved from 13.6% to 15%. Number of piglets per litter and mean birth weights tended therefore to be somewhat higher on farms where “hem” was not fed (10.1 and 1.5 kg), compared to farms where the sows were given “hem” (9.7 and 1.2 kg), whereas age and live weight at weaning were similar (Table 5). Vegetables such as water spinach, sweet potato vines, water hyacinth and banana pseudostems were always supplied for both feeding regimes.

 

 

 

Fattening pigs on farms that used “hem” and did not use “hem”

The amount of “hem” used varied, ranging from 4 to 39% of the diets (Table 6). The chemical composition of the diets supplemented with “hem” were also variable, with an average crude protein content of 13.9%, compared to 14.2 % on the farms that did not use “hem”. The lowest dietary CP value of 10% was found in the group “hem”. Concentrates were sometimes used by farmers that fed “hem”, but used by all producers not using “hem” (Tables 6 and 7). The initial weight and final weights were not different between the two groups (Table 8), although the time to slaughter and mean daily live weight gain of the “hem” group were significantly longer, probably due to the fact that they fed much less concentrate compared with producers not using “hem”.

 

 

 

 

 

 

 

Economic returns

Table 9 shows the differences in net incomes between farms using diets with or without “hem” for fattening pigs. Cost and return analysis shows that the use of concentrate is not profitable even though production parameters were superior compared with farms not using “hem”. 

Conclusions

• The survey showed that “hem” is a reasonably good protein source, but that it is rather low in dry matter.
• Pig performance on farms using “hem”was lower than on farms not using the by-product, but this was because farmers using “hem” fed little or no purchased concentrates
• As a by-product produced on the farm with little opportunity for sale (high water content) its value lies in helping to reduce feed costs
• The farmers who fed “hem” obtained a higher economic benefit, compared with producers who fed their pigs on concentrates, even though performance rates were lower.

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