Effect of level of fibre on performance and digestion traits in growing rabbits

Sustainable Farming: Nanofiber from the Pupunha Heart of Palm Sheath (Bactris gasipaes)-Enhanced Diets for Growing Rabbits and Their Health Impacts

The use of nanofibers in farm animal diets can enhance nutrient absorption, minimize environmental problems, and generate a sustainable source of income. In this study, we investigated the effects of the partial inclusion of nanofibers produced from the pupunha heart of the palm sheath (nanopupunha) in the diet of growing New Zealand White rabbits on zootechnical performance, organ morphometry, digestive content pH, intestinal histology, biochemical and immunological parameters, and cecum microbiota. Twenty-four male and female New Zealand White rabbits were distributed into the control group fed a basal diet with 14% crude fiber and treatment groups with the basal diet supplemented with 3.5% or 10.5% of nanopupunha, according to their initial weight. After euthanasia on day 42, we analyzed the pH of the stomach contents, jejunum, and cecum, and the relative weights of the digestive tract, liver, kidneys, and spleen. Duodenal and jejunal samples were collected for structural and ultrastructural analyses of the intestinal villi. Additionally, blood samples were collected to analyze blood glucose, cholesterol, triglycerides, and immunological analysis (IgG and IgM), and digesta samples from the cecum were collected to count enterobacteria and lactic acid bacteria. The inclusion of dietary nanopupunha did not affect the zootechnical performance of animals, but resulted in a linear decrease in the relative weight of the stomach and a linear increase in the relative weight of the spleen. No significant differences were observed in the pH of the digestive tract. Nanopupunha inclusion also resulted in a linear increase in the crypt depth of the duodenum, total mucosal thickness, and total cholesterol levels in growing rabbits. Including 10.5% of nanopupunha added to the diet showed the best results in terms of the intestinal health of the growing rabbits.

Effects of kudzu vine (Pueraria lobata) on the intestinal microflora and volatile fatty acids in meat rabbits

Adding flavonoid-rich kudzu vine (Pueraria lobata) meal to animal feed can improve intestinal microflora. Here, we investigated the effects of kudzu vine meal on the growth performance, caecal microbial diversity, caecal microbial number, intestinal pH, and volatile fatty acids (VFAs) of meat rabbits. Two hundred weaned Ira rabbits were randomly divided into four groups and fifty rabbits in each group. Meat rabbits in the control group (group A) were fed a basal diet without kudzu vine meal; those in the three test groups were fed experimental diets comprising 15% (group B), 25% (group C), and 35% (group D) kudzu vine meal. The results showed that the daily feed intake and mortality of meat rabbits decreased significantly after adding kudzu vine meal to their diet. The feed-to-gain ratio and mortality rate in 35% kudzu vine dietary were 3.5 and 7.5%, respectively, significantly lower than those in the control group. The Shannon and Chao 1 index of the bacterial diversity decreased significantly after adding kudzu vine meal to their diet. With the increasing amount of kudzu vine meal, the variety of dominant phyla did not change, but the relative abundance increased with the increase of kudzu vine addition. The intestinal total VFAs, acetic acid and propionic acid were the highest in 15% kudzu vine dietary, and significantly higher than those of 25% kudzu vine dietary. The content of total bacteria in 35% kudzu vine dietary was the lowest and the Escherichia coli and Salmonella showed a decreasing trend. In conclusion, our study confirms the adding kudzu vine meal significantly decreased the mortality rates and feed-to-gain ratio of meat rabbits, and fed diets with 25%-35% kudzu vine meal are recommended to achieve optimal results in meat rabbits.

Effect of Using Prickly Pear Seed Cake (Opuntia ficus indica L.) on Growth Performance, Digestibility, Physiological and Histometric Parameters in Rabbits

Prickly pear (Opuntia ficus indica L.) could be used in rabbit nutrition in compliance with circular economy principles, global warming issues, and reduction of production costs. This study aims to evaluate the effects of dietary incorporation of prickly pear seed cake (PPSC) on growth, physiological, and histometric parameters in rabbits. A total of 105 rabbits were divided into three experimental groups (n = 35) and fed different diets: a commercial feed (C group), the same feed with alfalfa replaced by PPSC at 10% (10PP group), and at 20% (20PP group). They were group-housed in cages with 5 animals per cage from weaning until slaughtering. While body weights and weight gains were similar in all groups, the coefficients of nutrient digestibility of dry matter, fibers, and ashes, as well as the characteristics of intestinal villi, were improved in the 10PP group compared to the others (p < 0.05). The 20PP group showed a reduction in perirenal and interscapular fat (p < 0.05), as well as lower plasma concentrations of triglycerides and cholesterol compared to the C group (p < 0.001). In conclusion, PPSC can be incorporated into the diets of growing rabbits up to 20% as a partial substitute for alfalfa without the impairment of growth performance. Additionally, the inclusion of PPSC enhanced nutrient digestibility and increased the intestinal absorption surface area.

Inclusion of Soybean Hulls (Glycine max) and Pupunha Peach Palm (Bactris gasipaes) Nanofibers in the Diet of Growing Rabbits: Effects on Zootechnical Performance and Intestinal Health

This study evaluated the inclusion of nanofibers from soybean hulls and pupunha peach palm heart sheaths in the diet of growing rabbits. Twenty-four New Zealand White rabbits (male and female) were allocated in three experimental groups: control, fed a basal diet; Nanosoy, fed a diet containing 7% soybean-hull nanofibers; and Nanopupunha, fed a diet containing 7% pupunha palm heart-sheath nanofibers. The Nanosoy-group rabbits showed poorer final weight, daily feed intake, and daily weight gain than those in other groups. In the duodenum, villus height, total mucosal thickness, and villus width were higher in rabbits that received nanofiber-supplemented diets than in the controls. Higher villus density and wall thickness were observed in Nanopupunha-fed rabbits than in the controls. In the jejunum, although the crypt depth was higher in Nanosoy-fed rabbits, the villus height:crypt depth ratio was higher in the Nanopupunha-fed group. Nanosoy-fed animals exhibited increased count Enterobacteriaceae populations. Rabbits in both nanofiber-fed groups exhibited higher lactic-acid bacterial counts than those in the control-diet group. Therefore, although the inclusion of 7% Nanopupunha in the diet of rabbits did not alter the performance, it improved intestinal health and increased the lactic-acid bacterial count in the cecum of growing rabbits.

Effect of varying the energy density on growth performance, meat quality, caecum fermentation and microbiota of growing Rex rabbits

An experiment was conducted to determine the effects of varying the digestible energy (DE) density on growth performance, meat quality, caecum fermentation and microbiota in 3–5-month-old Rex rabbits. One-hundred and eighty 3-month-old Rex rabbits were allocated in individual cages to five treatments with diets having DE levels (MJ/kg as-fed basis) of 9.46, 9.97, 10.46, 10.94 and 11.43, respectively. The results showed as follows: with increasing DE concentration the average daily gain, muscle pH value of 45 min post-mortem, caecal pH value and NH3-N concentration increased (P < 0.05). Bacterial denaturing gradient gel electrophoresis (denaturing gradient gel electrophoresis) of partial 16S rRNA genes profiles were clearly different among different treatments, which suggests that the population of microorganism in the caecum was influenced by the dietary DE density.

Effect of diets on growth, digestibility, carcass and meat quality characteristics of four rabbit breeds

The current study was conducted to evaluate three diets using four rabbit breeds. A total of 320 male weaned rabbits representing four breeds named V-line, Saudi-1, Saudi-2 and Saudi-3 were randomly distributed into three comparable dietary treatments. Three levels of indigenous feedstuffs (IFS) of 42.5%, 65% or 87.5% (alfalfa hay, barley and wheat bran) were substituted for the same levels of non-indigenous feedstuffs in the diet (corn grain, soybean, molasses, and limestone) to form three diets named D1, D2 and D3, respectively. These dietary treatments were used to evaluate post-weaning growth performance, feed intake, feed conversion, carcass and lean composition, and nutrients digestibility in four rabbit breeds. Partial replacement of IFS with non-indigenous feedstuffs attained significant increase in growth performance. The diet containing 87.5% IFS led to significant increase in daily weight gains by 8.4, 4.0, 8.1, 6.2 and 6.7 g at age intervals of 5-6, 7-8, 9-10, 10-11 and 11-12 weeks compared to the control diet, respectively. The diet containing 87.5% IFS showed a significant reduction in feed conversion ratio compared to control diet during the experimental periods. The diet containing 65% IFS showed significant increases in pre-slaughter weight (112 g) and hot carcass weight (89 g), while dressing percent, offal weight and percent, and non-carcass weights and percentages (head, fur, legs + tail, viscera) were not significantly different. The diet containing 87.5% IFS gave an increase of 1.1%, 6.4%, 8.8%, 17.9%, 7.4%, and 19.6% in digestibility coefficients of organic matter (OM), crude protein (CP), neutral detergent fibre (NFD), acid detergent fiber (ADF), hemi-cellulose (HC) and cellulose (C) compared to control diet, respectively. Feed intakes were moderate and ranged from 69 to 124 g for V-line, 77 to 128 g for Saudi-1, 79 to 130 g for Saudi-2, and 76 to 119 g for Saudi-3 along with moderate ratios of feed conversion ranging from 2.65 to 3.80, 2.45 to 3.90, 2.46 to 3.79 and 2.63 to 3.65, respectively. Pre-slaughter weight, hot carcass weight, and offal weight were in favour of Saudi-2 rabbits compared to the other groups. Both Saudi-1 and Saudi-2 rabbits were slightly higher than Saudi-3 in weights and percentages of head, fur, viscera and legs + tail. Lean and bone weights and percentages and meat to bone ratio in Saudi-2 carcasses were slightly higher than those recorded in the other groups, while moisture, DM, CP, EE and ash contents in the lean have shown little differences between groups. Rabbits of Saudi-1 were ranked the first in digestibility coefficients of OM, CP, NDF, ADF, HC, C and cell count compared to other groups. Rabbits of Saudi-2 fed diet containing 87.5% IFS recorded the heaviest body weights and gains since this class showed considerable deviations in body weights of 345, 341, 269, 307, 321, 345 and 347 g at 6, 7, 8, 9, 10, 11 and 12 weeks of age, respectively, in comparison with the lightest class. Both Saudi-2 and Saudi-3 rabbits fed the diet containing 87.5% IFS had favourable estimates of feed conversions ranging from 2.1 to 3.4, while rabbits of Saudi-1 fed the diet containing 87.5% IFS recorded the best digestibility coefficients.

Microbial ecosystem and fermentation traits in the caecum of growing rabbits given diets varying in neutral detergent soluble and insoluble fibre levels

The effect of the level of neutral detergent fibre (NDF: 0.35, LI and 0.42, HI) and neutral detergent soluble fibre (NDSF: 0.14, LS and 0.17, HS) in the caecal ecosystem was studied in 24 weaned (28 days of age) rabbits, weighing 630 ± 80.2 g in a 2 × 2 factorial design. After 22 days, rabbits were slaughtered and their caecal contents sampled. The caecal pH (on average 6.2) and molar volatile fatty acids (VFA) proportions were not affected by dietary treatments, but total VFA concentration tended to be lower with NDF (84.7 vs. 74.1 mmol/l; P = 0.095). The amount of total bacteria tended (P = 0.075) to increase with NDSF, but only in diets with 0.35 NDF. The caecal proportions of Ruminococcus albus and Fibrobacter succinogenes were not affected by type or level of fibre, but Butyrivibrio fibrisolvens decreased (P = 0.055) with the NDF proportion in LS diets. Denaturing gradient gel electrophoresis (DGGE) analysis showed that bacterial communities clustered according to each combination of NDF and NDSF, but did not greatly differ among diets (similarity indexes between 0.67 and 0.70), nor biodiversity was affected (average Shannon and richness indexes 3.50 and 33.1; P > 0.10). Archaeal population revealed changes in the amount and composition that were particularly evident in HS diets, decreasing in concentration (from 4.37 to 4.12 log10 gene copy number/g) and biodiversity (Shannon index from 3.14 to 2.52 and richness index from 23.7 to 13.9) compared to LS. The type and level of dietary fibre had a minor impact on caecal fermentation traits or caecal bacterial community. However, the increase in NDSF from 0.14 to 0.17 reduced concentration and diversity of methanogenic archaea.

Effect of dietary inclusion of sorghum milling waste on growth response, nutrient utilisation, gut characteristics and cecal microflora of weaner rabbits

Growth response, nutrient digestibility and cecal microflora of 80 male, mixed breed weaner rabbits fed with varying dietary inclusions of sorghum milling waste (SMW) was investigated. Four experimental diets were formulated such that SMW was included at 0 (control), 100, 200 and 300 g/kg, respectively. Each dietary treatment was performed on 20 rabbits. Feed intake increased (P < 0.05) while final live weight and feed conversion ratio of rabbits decreased (P < 0.05) following increased dietary inclusion of SMW. Rabbits fed with 100 and 200 g/kg SMW had similar feed conversion ratios, weight gain, crude fiber, dry matter and crude protein digestibility values. Rabbits fed with 300 g/kg SMW recorded the lowest (P < 0.05) hot carcass weight, dressing percentage and rack weight. Similar dressing percentage and rack weight were recorded for rabbits fed with control diet, 100 and 200 g/kg SMW. The weight of cecal content increased (P < 0.05) with increased dietary inclusion levels of SMW. Rabbits fed with 300 g/kg SMW recorded the lowest (P < 0.05) coliform and lactobaccillus counts. Dietary inclusion of up to 200 g/kg SMW supported improved growth response and carcass yield without imposing any detrimental effect on cecal microflora.

Digestive physiology and hindgut bacterial community of the young rabbit (Oryctolagus cuniculus): effects of age and short-term intake limitation

The digestive response of the young rabbit to a short-term (28-53 days) limitation of its voluntary intake (25%) was analysed according to age and in relation to the incidence of digestive troubles. Several physico-chemical parameters of the caecal biotope were studied in relation to the caecal bacterial community structure and diversity, and with other physiological criteria (stomach pH, ileum morphometry and maltase activity). The morphometry of the ileum was significantly affected by age (36 vs. 52 days) but not by the intake level, while the relative maltase activity remained unchanged. In the stomach, the pH of antrum and fundus increased by approximately 1/3 between 36 and 52 days, and was 31% (P=0.003) and 79% (P<0.001) higher for restricted compared to ad libitum rabbits respectively. However the caecal pH remained unchanged (mean: 5.83). The caecal redox potential increased slightly, by 8 units (P=0.02), when intake was limited, but did not change between 36 and 52 days. The caecal bacterial diversity increased with age (4.8 vs. 5.2, P=0.014) while bacterial structure was modified. Limiting the intake for 16 days did not modify the structure or the diversity of the bacterial community.