Rabbit feed nutrition study for intensive, large-scale meat rabbit breeding

Guan Xiangmei

Qingdao Kangda Food company Limited,Kangda Group, Qingdao,266400, China
qdjngxm@126.com

Abstract

This article provided the energy requirement, the ratio of protein and energy, the reasonable content of cellulose and amylaceous for growing rabbits and different staged reproductive female rabbits based on the research data at home and abroad, combining the rabbits feeding practice of Kangda Food Company Limited in Qingdao, considering the index of production and health of rabbits group.

Key words: intestinal health, meat rabbits, nutrition, requirement

Introduction

There is significant difference between intensive and traditional culture in meat rabbits breeding, especially on nutrition supply. Breeding industry was perplexed by feed nutrition in scale breeding. For example, in order to increase the growth rate, the energy was increased in commercial rabbits, the result was the increase of death rate; poor constitution of the female rabbits in late lactation that even influenced the next service; low litter weight of weaning with stunted growth. All these feed nutrition problems were usually met in practical. Feed nutrition problem met in rabbits scale breeding was investigated, with rabbits farming practical experiences and the development of feed nutrition technique at home and abroad.

Energy requirement

Same as pig and chicken raising, energy is also the important index of determining growth rate and reproductive performance in rabbits.

Energy requirement of growing rabbits

There is difference in energy requirement for growing rabbits with different experiments and detected methods. Partridge et al. reported that the measured value of New Zealand rabbits and California rabbits was 400 MJ DE/Kg^0.75；Scheele et al. found that the maintenance requirement under high temperature decreased greatly comparing with that under normal temperature, which was 345 and 413 MJ DE/Kg^0.75. respectively.

It is known that the range of synthetic energy efficiency for protein and fat are 38-45% and 64-70% respectively, De-blas put forward that the average energy efficiency of growing rabbit was 56%, and he also calculated the average energy requirement in fattening period (table 1). According to his determination, baby rabbits weaning weight at 0.6 kg , if its daily gain want to increase to 40 g, then the energy requirement was 1249 kJ everyday. If the diet metabolic energy was 9.5 MJ/Kg, then the daily feed intake was 131 g. If the energy concentration was too low (lower than 9.2 MJ/Kg), rabbits could not increase feed intake any more by the affection of gastric volume. So daily gain at 40g can not be achieved.

Energy requirement of reproductive female rabbits

The energy requirement of reproductive female rabbits is maintenance plus lactation plus pregnancy plus young rabbits growth. Parigi-Bini et al. (1991) found that the maintenance requirement of digestive energy are 398, 431, 432, 468 MJ DE/Kg^0.75 respectively for vacant, pregnant, lactational, lactational plus pregnant female rabbits.

The total energy requirement of pregnant female rabbits depend on the development of fetus and placental during pregnant period, in the first 21 days, fetus development is slow, female rabbits can forage feed to satisfy its requirement at this time. 21 days later, on one side, nutrition requirement quickly increase following fetus' quickly growth, on the other hand, the feed intake of female rabbits are decreased, affected by abdomen capacity. In the last week, female rabbits start to mobilize reserved energy in order to meet the need of fetus, so female rabbits need to reserve energy in the early pregnant period. According to the research of Kamphues, in the early pregnant period, the pregnant and reserved energy requirement is 140 MJ DE/Kg^0.75. The suitable energy requirement of pregnant female rabbits at the last week (with 9 fetus)will be twice the maintenance energy ,considering the reserved energy.

The energy requirement of lactational female rabbits depends on amount of lactation, lactic component and the lactating efficiency of digestive energy in diet. Amount of lactation depends on lactational stage, the size of young rabbits nursed, the physiological stage of female rabbits and feed intake (see table 2). Other influencing factors are breed, multiparity and individual difference of female rabbits. The energy content in milk mainly depends on lactation days, each kg milk contains 8 MJ in the first three week, later, energy content will increase following the depress of lactation quantity. After parturition, to vacant female rabbits, energy content increase to 10 MJ; to pregnant female rabbits, energy content is about 14.5 MJ. At the end of the fourth lactating week, the energy availability for lactation is generally 63-69% in the conventional diet.

According to above principle and data, Lebas summarized the total energy requirement of breeding female rabbits in different physiological condition (table 2).

According to the above table, we can see the feed requirement to different nutrition concentration for female rabbits in different stage; For example, for the multiparity female rabbits with body weight at 4.0 kg, energy requirement at the fourth week is, maintenance energy - 1.19 MJ, pregnancy energy -1.19 MJ,which amount to 2.38 MJ every day. If energy content is 10.5 Mcal /kg in diet, then the feed intake is 227 g every day. Meanwhile we can see, in the early pregnant days, in order to prevent excess fat, appropriate feed limiting is needed for female rabbits in the premise of ensuring the necessary energy reserve. In the early lactation stage, female rabbits need to increase feed intake gradually. It is known from the table, the energy requirement is 4.9 MJ for female rabbits at 4 kg at lactation peak time, if the feed concentration is 10.5 MJ/kg, 466 g is needed to forage. If the digestive energy in diet is less than 9.5 MJ/kg, then feed intake is larger than 516 g. Restricted by the gastric volume, the nutrition requirement usually can not be achieved by feed intake, at this time female rabbits begin to lose weight and emaciate. Especially for primiparity female rabbits, low feed intake will lead to more serious weightlessness, the more seriously lactation body loss will make it even worse, so it is better not to blood mate for primiparity female rabbits. For frequentative reproductive meat rabbit does, nutrition should ensure the embryos in the abdomen first, after lactation 20 days, which is also the later period of fetal development when nutrition supply mostly for fetus, lactation quantity descend quickly, so, the baby rabbit must be weaned before 28 days. Between 21 and 28 days, for the feed intake descending, fetal development, lactation need, female rabbits are easy to lose weight. at this time, energy concentration in diet is need to be enhanced. From our practical experience , good effect can be obtained through adding vegetable fat with the supplement of sugar to prevent cetonemia originated by lipodystrophia in the body. Relatively speaking, semi-frequentative reproduction,  the mating model adopted in Kangda Company Limited ,is favourable for body condition, that is mating at 19 th day after labour, weaning at 35th day, giving the female rabbits 18 days to rest.

Proteinic nutritional requirement

Protein digestibility from different source distincts tremendously, so it is more scientific to use digestible protein than crude protein in evaluating the feed nutrition.

Growing rabbit

The practice shows that young rabbits (four to eight weeks) is larger than fattening rabbits in amino acid requirement. Considering the health of intestinal tract, crude protein concentration in diet should be lower than that for fattening rabbits (16 and 16.5 respectively), when protein level is lower than 15.5%, the growing rabbits weight gain descend obviously. The ratio of protein and energy of diet is very important for meat rabbits, too high or too low will lead to two bad effect, one is to influence the index of production directly, the other is to increase death rate obviously. According to the research of De Blas, the ratio of digestible protein and digestive energy is suitable at 10.8 in diet.

The reproductive female rabbits

The results show that the ratio of digestible protein and digestive energy is suitable at about 12 for breeding female rabbits, but it should follow the changing breeding plan to alternate slightly. The content of digestive energy is10.5 MJ/kg and the digestible protein is 126 g/kg in the optimum performance diet ,with estimated average proteinic digestibility at 73%, then the crude protein content in diet should reach 17.2%, if you want to gain good breeding performance in production, protein level is needed to maintain at 17-18% for female rabbits. The practice shows, when the feed was with low protein level (lower than 15%) or low protein energy ratio, it might cause performance depress. The prominent phenomenon is shown in low lactation quantity, low weaning weight, low conception rate. When fed high protein level diet(higher than 18.5%), it had adverse effect on intestinal tract health of female rabbits and survival rate for young rabbits, meanwhile, excess protein was resolved to urea, with the action of bacteria in dung, urea was decomposed to poisonous alkaline air, which is easily to cause respiratory tract disease.

Starch requirement

Starch is the important energy source for feed, but its content should be controlled reasonably in rabbit feed. When fed high starch diet, it might cause hindgut carbohydrate overexertion, leading to intestinal tract bacterial flora alternation, bringing about pathogenic bacterial growth and development, finally generating intestinal tract disease in rabbit group. De Blas et al. reported that ileum starch digestibility not only depend on age, but also depend on diet composition and starch source. Contrasting with corn and barley as the base diet, the starch digestibility of the former is lower, leading to high ratable corn starch to hindgut, especially in early fattening stage(3-7weeks), so corn starch should be controlled in production. The practice shows, when fed high starch in weaning diet, the death rate increases obviously. Lebas et al. demonstrated, when starch content increased from 15 to 25%, the death rate increased from 4.9 to 12%. The suggested starch content in weaning diet is lower than 14% in production.

Cellulose requirement

Rabbit is single stomach herbivore, its digestive system is suitable for high cellulose diet. Many experiments have indicated, high cellulose diet was favourable for depressing death rate, the mechanism of action is to stimulate ileum－appendix vigor and avoid chyme excess residence time. However, excess cellulose diet is unfavourable for rabbits, because digestive energy content will depress generally at this time, forming too high protein energy ratio, this condition will precipitate digestive tract disorder by the breeding of microbial population, leading to digestive tract disease. T.Gidenne investigated the fiber requirement in fattening rabbits diet (see table 3).

Low digestive part (cellulose and lignin) may reduce digestive tract disorder and death rate. Gidenne et al.1998）indicated, when ADF depressed from 19% to 15%, fattening rabbit death rate plus disease rate increased from 18% to 28%. Although the intake of lignified cellulosic decrease digestibility obviously, it is still necessary to remain reconstruction its content in production.

Fat requirement

It is usually needed to add fat to make digestive energy achieve above 9.0 MJ/kg in the premise of high fiber content as well as controlled starch in rabbit feed, we know that energy level is the main factor of controlling feed intake in rabbit feed, rabbits can manage to adjust feed intake following energy concentration in diet to achieve permanent ingestional energy everyday. Nevertheless, Maertens investigated that this regulation of feed intake was possible only when digestive energy was above 9.3 MJ/kg, hence, it can achieve better effect to add 1-3% fat to female and fattening rabbit feed in production.

Mineral matter requirement

Mineral matter needed by rabbits includes macroelement and microelement. Lucerne is a good source of calcium and manganese and so on. Grain seed, especially grains by-product, such as wheat bran and rice bran are high-grade phosphorus sources. So, if the key raw material in rabbits feed are lucerne, grain and bran, mineral deficiency usually seldom happen. Microelement can meet need without achieving the recommended addition. But if  some cheap crude fiber like peanut shell are used to replace lucerne, microelement is need to add as the recommended addition in production. It will cause phosphorus deficiency when female rabbits are fed the diet which phosphorus content is lower than 0.47%, the over added mineral matter will influence palatability. Mineral matter requirement of lactational female rabbits is higher than that of fattening rabbits, but Lebas indicated that excess calcium(≥40g/kg) or phosphorus(≥19g/kg) could cause the decrease of conception rate and litter size or the increase of death rate obviously.

Vitamin requirement

Vitamin is divided into lipovitamin and water-soluble vitamin. Water-soluble vitamin can be synthesized by microorganism in intestinal tract. In traditional  breeding culture, rabbits can get all needed B cluster vitamin from foraging soft dung and diet. In intensive breeding culture, high performance lead to high vitamin requirement, so it need suitable addition in diet. lipovitamin can not be synthesized in body, it need to be added in diet according to recommended quantity for different rabbit breed in order to ensure normal growth and reproductive ability for meat rabbit. However, it need to avoid V_A poisoned originated by repeat ponderosus addition.

Conclusion

All nutrient should be overall considered in designing feed formula in production, we should not emphasize on some nutrition index unilaterally, nutritive equilibrium is favourable for meat rabbit production.

References

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