Effect of stocking density on performance, infection by Eimeria spp., intestinal lesions and foot pad injuries in broilers with outdoor access under tropical conditions.

1. The study was carried out to evaluate the effect of stocking density on performance, litter moisture, Eimeria oocyst shedding, intestinal and foot lesions in broilers.2. A total of 192 1-d-old male Cobb broilers were distributed with three different stocking densities (6, 8 or 10 chickens/m2) with outdoor access and eight replicates in a completely randomised design over two periods. Productive parameters were measured from 3 to 7 weeks of age.3. Oocyst counts (OPG) in both excreta and litter were performed at 3, 4 and 5 weeks of age. Intestinal and foot pad lesions were evaluated at 7 weeks old. The stocking density of 6 birds/m2 had the highest body weights (P < 0.05) (2129 ± 37.67, 2759 ± 50.82 and 3167 ± 75.64 g at weeks 5, 6 and 7 of age, respectively).4. Feed intake decreased with increasing stocking density at week 3 (r = -0.57), 4 (r = -0.48), 5 (r = -0.84), 6 (r = -0.68) and 7 (r = -0.65) of age (P < 0.05). Birds with stocking densities of 8 and 10/m2 consumed, respectively, up to 11% and 19.5% less feed than the lower stocking density groups.5. Stocking density affected (P < 0.05) feed conversion (1.61, 1.49 and 1.46) and litter moisture (40.88, 52.60 and 56.19%) at 3 weeks of age. Neither carcase yield nor mortality was different between densities (P > 0.05). Likewise, there was no effect of stocking density on OPG neither in excreta nor in litter, intestinal lesions, or foot pad and hock injuries (P > 0.05).6. In conclusion, the higher stocking density decreased both the feed intake and the live weight in broilers, but there were no effects in the number of Eimeria OPG in excreta or litter, neither intestinal lesions nor in foot pad injuries.

Impact of Dietary Condensed Tannins and Haemonchus contortus Infection in Growing Sheep: Effects on Nutrient Intake, Digestibility, and the Retention of Energy and Nitrogen.

PURPOSE: A controlled study evaluated the effect of condensed tannins (CT) from Gymnopodium floribundum leaf meal (GF), infection with Haemonchus contortus (I) and their interaction, on feed intake, diet digestibility and retention of N (NR) and energy (ER) in hair sheep lambs. METHODS: Thirty-six, worm-free hair sheep lambs (14.9 ± 1.56 kg body weight) were housed in metabolic cages. Eighteen animals were infected with 6000 H. contortus L3, while other 18 lambs were kept non-infected. On day 28th post-infection (PI), infected lambs were assigned to three diet groups: a diet without GF (I-NONGF), a diet with GF (I + GF) and a diet with GF + polyethylene glycol (PEG) (I + GF + PEG). Non-infected (NI) lambs were assigned to similar diet groups: NI-NONGF, NI + GF and NI + GF + PEG. The packed cell volume (% PCV), ante-mortem faecal egg counts and post-mortem worm burdens were also evaluated. RESULTS: Infection did not affect digestibility, NR and ER. Meanwhile, CT intake from the GF diet reduced the digestibility of dry matter, organic matter and crude protein, as well as NR, compared to lambs consuming the NONGF and GF + PEG diets (P < 0.05). Although, the digestible energy was similar between lambs consuming NONGF and GF + PEG diets, the ER was higher for lambs consuming the control NONGF diet. Diets did not affect the PCV, or the ante-mortem and post-mortem parasitological variables. CONCLUSION: The costs on N and energy metabolism were mainly associated with the CT content of the GF diet, but other features of the diet such as the high lignin content, seemed to affect animals consuming GF meal. Meanwhile, the H. contortus infection had a non-significant impact.

Nitrogen retention in hair sheep lambs with a gradient of Haemonchus contortus infection.

The impact of Haemonchus contortus infections on nitrogen retention (NR) of hair sheep lambs is unknown. This study estimated the feed intake, digestibility, NR, haematocrit (HT), and their relationship with the gradient of H. contortus infection in hair sheep lambs. Twenty-four hair sheep lambs, 3-4 months old, reared parasite-free were used (live weight (LW) 16.7 ± 1.7 kg). Six lambs were kept parasite-free, nine lambs received a dose of 300 H. contortus infective larvae (L3)/kg LW, and the remaining nine lambs received 500 H. contortus L3/kg LW. Infection doses ranged from 3870 to 9,500 L3. Lambs were individually fed for an average daily gain (ADG) of 100 g. On days 1 (P < 0.01) and 7 (P < 0.001) post-infection (PI), the L3 doses were positively associated with HT, possibly due to platelet recruitment. On week 1 PI, the infection (L3) reduced the crude protein (CP) intake (g/kg metabolic LW) (P < 0.05). A reduction of 1% HT corresponded to 1200 eggs per gram of faeces (EPG) for day 21 PI (P < 0.05), 2300 EPG for day 28 PI (P < 0.001), 2400 EPG for day 35 (P < 0.001), and 1300 EPG for day 41 PI (P < 0.001). However, the HT levels were never lower than 21 %. A lower CP digestibility was associated with EPG only on week 5 PI (P < 0.05). There was no significant association between EPG, Total egg in faeces, or worm burden (WB) with intake, dry matter digestibility (DMD), ADG or NR. The NR of lambs was positive along the different weeks of study irrespective of infection level. The WB was negatively associated only with HT on day 41 PI (P < 0.001), where a 1 % HT reduction was estimated for every 257 worms hosted. In conclusion, no relationship was found between H. contortus infection and DMD, ADG or NR in hair sheep lambs. The cost of H. contortus infection resulted only from the HT reduction and depended on the gradient and stage of the infection.

The effects of outdoor access and stocking density on the performance of broilers reared under tropical conditions.

1. The effects of housing system and stocking density on growth performance and carcase yield of a commercial strain of broiler chickens reared under tropical environmental conditions may differ from temperate conditions.2. In two experimental periods, carried out during two contrasting seasons of the year (winter and summer), 240 Cobb 500 male chickens were randomly assigned in groups of 60 to 1 of 4 treatments, with 6 replicates in each, low stocking density with outdoor access (LO, 5 birds/m2); high stocking density with outdoor access (HO, 10 birds/m2); low stocking density indoors (LI, 5 birds/m2); high stocking density indoors (HI, 10 birds/m2). From 21 to 42 d old, body weight (BW) and feed intake (FI) were weekly recorded. Mortality was measured daily and carcase weight at slaughter. Indoor and outdoor temperature and relative humidity were measured daily.3. There was a tendency for chickens raised in the outdoor access to be heavier than those raised in the indoor treatments. Chickens raised in the low-density treatments in the first experimental period were significantly heavier, gained more weight and had lower value for feed conversion ratio (FCR) than those reared at high density. In the second experimental period mortality significantly increased on week 4 due to heat stress. Birds raised with outdoor access had an increased carcase yield compared to those raised exclusively indoors.4. In conclusion, low stocking density in combination with low environmental temperatures had enhancing effects on BW, BWG, FI and FCR, and the effects of housing system depended on stocking density. Low stocking density and outdoor access had positive effects on carcase yield.

Gymnopodium floribundum fodder as a model for the in vivo evaluation of nutraceutical value against Haemonchus contortus.

This study validated a protocol to identify the nutraceutical value of Gymnopodium floribundum (GF) foliage based on its effects on sheep nutrition, production and health and its impact on adult Haemonchus contortus. Thirty animals (17.8 ± 3.44 kg BW) were distributed into five experimental groups (n = 6). Groups T1-T3 received feed including 20%, 30% and 40% GF content, respectively, and group T4 received feed with 0% GF. Groups T1-T4 were all infected with 6000 H. contortus infective larvae (L3). Group T5 included six worm-free lambs fed a diet without GF. Feed intake, dry matter digestibility (DMD) and organic matter digestibility (OMD) were measured, in addition to the faecal excretion of eggs per gram (EPG) and total faecal egg count (TFEC) of H. contortus. On day 39 post-infection, lambs were humanely slaughtered to recover and count adult parasites and assess the length and fecundity of female worms. Higher levels of GF in the diet reduced DMD and OMD (P < 0.05), with the lowest values in T3 (40% GF) (P < 0.05). Body weight gain was similar for all groups (0.18 to 0.2 kg/day; P > 0.05). EPG and TFEC were lower in T1 and T3 than in T4 (P < 0.05), and the number of adult female worms was lowest in T3 (P < 0.05). In conclusion, GF leaf meal can be considered a nutraceutical when included at 40% (T3) in the diet of lambs, based on its ability to decrease the EPG and TFEC of H. contortus by reducing the female worm burden. A 40% inclusion level had no negative impact on lamb diet intake, production and health, although a reduction of digestibility was observed.

Impact of gastrointestinal parasitism on dry matter intake and live weight gain of lambs: A meta-analysis to estimate the metabolic cost of gastrointestinal nematodes.

This study aimed to estimate the effect of gastrointestinal nematodes (GIN) on the productive performance assessed by the live-weight change (LWC) of lambs, and the metabolic cost associated with parasitism by means of a meta-analysis. Data used in the meta-analyses were obtained from twenty papers selected using the following criteria: (a) lambs with (I) and without (NI) GIN; (b) lambs fed ad libitum; (c) LWC data; (d) feed consumption data; and (e) chemical composition of diets. The effect of diet composition (crude protein [CP] and metabolizable energy [ME]) on dry matter intake (DMI), and the effect of composition and nutrient intake (DMI and CP intake [CPI]) and ME intake (MEI) on LWC was evaluated using respective regression analyses. The metabolic cost of worm burden was determined as the difference in CP and ME requirements between NI and I lambs for each adult parasite. The CP and ME cost were evaluated for lambs at two different levels: maintenance level 0 g LWC and 100 g LWC. The worm burden had an impact on the DMI and LWC of lambs (P < 0.05). The association of CP x infection level was the best predictor of DMI. The association between MEI and infection level were the best predictors of LWC. The metabolic cost of GIN increased to 0.30 mg CP/kg LW0.75 and 0.0056 kJ ME/kg LW0.75 for each adult parasite. The metabolic cost was not modified by diet quality (maintenance level 0 g LW/day or 100 g LW/day). In conclusion, GIN has a negative effect on DMI and LWC. The metabolic cost of GIN infection can be covered by supplying the additional requirements for protein and energy in the diet of infected lambs.

Estimating Apparent Nutrient Digestibility of Diets Containing Leucaena leucocephala or Moringa oleifera Leaf Meals for Growing Rabbits by Two Methods.

This study aimed to evaluate the nutrient digestibility of growing rabbits fed diets with different levels of either Leucaena leucocephala (LLM) or Moringa oleifera (MOLM) leaf meals and also to compare total collection and TiO2 marker methods for estimating digestibility. A total of 30 California growing rabbits (1.81±0.19 kg live weight on average) were randomly distributed into five experimental groups of six rabbits each and were housed in individual cages. The groups were control, 30% LLM, 40% LLM, 30% MOLM, and 40% MOLM. All groups received pelleted diets for two weeks; diets also contained 4 g/kg titanium dioxide as dietary marker. Daily feed intake was recorded during the whole experimental period and total feces were collected daily and weighed individually during four days. The results showed that there were no difference (p>0.05) in feed, dry matter (DM), organic matter (OM), crude protein (CP), digestible energy, and crude fiber (CF) intake between the control group and the other experimental groups. The apparent digestibility values of DM, OM, CP, CF, acid detergent fiber, and gross energy were the highest for control group (p = 0.001), meanwhile MOLM diets had generally higher nutrient digestibility coefficients than LLM diets. Increasing the inclusion level of leaf meal in the diet from 30% to 40% improved the digestibility of CF from 45.02% to 51.69% for LLM and from 48.11% to 55.89% for MOLM. Similar results for apparent nutrient digestibility coefficients were obtained when either total collection or indigestible marker method was used. In conclusion, the digestibility of MOLM containing diets were better than LLM diets, furthermore TiO2 as an external marker could be used as a simple, practical and reliable method to estimate nutrients digestibility in rabbit diets.

Determination of tropical forage preferences using two offering methods in rabbits.

Two methods of feed preference trials were compared to evaluate the acceptability of 5 fresh foliages: Leucaena leucocephala, Moringa oleifera, Portulaca oleracea, Guazuma ulmifolia, and Brosimum alicastrum that was included as control. The evaluation included chemical analyses and forage intake by rabbits. The first method was a cafeteria trial; 12 California growing rabbits aged 8 wk, allocated in individual cages, were offered the five forage plants at the same time inside the cage, while in the second trial 60 California growing rabbits aged 8 wk, allocated individually, were randomly distributed into 5 experimental groups (n = 12/group); for each group just one forage species was offered at a time. The testing period for each method lasted for 7 d, preceded by one week of adaptation. The results showed that B. alicastrum and L. lecocephala were the most preferred forages while on the contrary G. ulmifolia was the least preferred one by rabbits. The results also revealed that the CV% value for the 2nd method (16.32%), which the tested forages were presented separately to rabbits, was lower and methodologically more acceptable than such value for the 1(st) method (34.28%), which all forages were presented together at the same time. It can be concluded that a range of tropical forages were consumed in acceptable quantities by rabbits, suggesting that diets based on such forages with a concentrate supplement could be used successfully for rabbit production. However, growth performance studies are still needed before recommendations could be made on appropriate ration formulations for commercial use.

Effect of three protein levels and an enzyme blend on egg quality of laying hens.

One approach to enhance the Crude Protein (CP) value of laying hens diets it is the use of enzymes. The objective of this experiment was to evaluate different CP levels and an enzyme blend (Avizyme; AZ) in laying hens diets on egg quality. Two hundred and eighty eight ISA Babcock B-300 hens were used. The diets were: (A) 18.8% CP, (B) 18.8% CP+AZ, (C) 16.6% CP, (D) 16.6% CP+AZ, (E) 16.0% CP and(F) 15.4% CP. Data were analyzed using analyses of variance for factorial designs (Diets A, B, C and D) and a complete randomized design (Diets C, E and F). CP or AZ had no effect on egg quality (p>0.05). Reduction of CP in laying hen diets tended (p<0.08) to increase feed intake (90.8, 93.6 and 96.5 g day(-1)) and feed conversion (p<0.05) (2.1, 2.2 and 2.3) for 16.6, 16.0 y 15.4% of CP, respectively. Reduction of CP in laying diets increased (p<0.05) albumen height (11.4, 11.9 y 11.9 mm). Significant (p<0.05) reductions of feed intake (96.2 vs 89.9 g day(-1)) and feed conversion (2.1 versus 2.0) in diets supplemented AZ were observed. Significant (p<0.05) interactions of PC and AZ on feed intake and feed conversion were found. The reduction of CP in the diets did not affect egg quality, but has an effect on feed intake and feed conversion. Avizyme supplementation reduced feed intake and improve feed efficiency in high CP diets.

Productive performance of Creole chickens and their crosses raised under semi-intensive management conditions in Yucatan, Mexico.

1. The productive performance of 4 chicken breed groups managed under semi-intensive conditions in Yucatan, Mexico was evaluated. Thirty-six mixed chickens, one week of age of each of the 4 breed groups (Creole, F1 Hubbard x Creole, 7/8 Hubbard x 1/8 Creole and Hubbard) were used. 2. During 1 to 3 weeks of age all birds were fed on a diet containing 210 g/kg crude protein (CP) and 12.95 MJ/kg metabolisable energy (ME). From weeks 4 to 7, they were given a diet with 190 g/kg CP and 12.55 MJ/kg ME. Food consumption and live body weight were recorded weekly. Statistical analysis of the data was performed according to complete randomised design and means comparison using Tukey test was carried out when necessary. 3. Creole chicks had the lightest weights at all ages as compared to their crosses and the Hubbard birds. At 7 weeks of age, Creole chicks were 2.11, 2.44 and 2.90 times lighter than their contemporary F1, 7/8 Hubbard x 1/8 Creole and Hubbard birds, respectively. Hubbard birds were heavier than F1 and 7/8 commercial x 1/8 Creole birds, and the latter group heavier than the F1 birds. Similarly, Creole chicks had the lowest growth rate compared to the other genetic groups. Heterosis for body weight up to 7 weeks of age was 8.2%. 4. Feed consumption was also lower for the Creole chicks at all ages. Food:gain ratio, however, was higher for the Creole chicks at all ages. Food:gain ratios from weeks 2 to 7 were 2.18, 2.65, 3.04 and 4.36 for the Hubbard, 7/8 Hubbard x 1/8 Creole, F1 and Creole birds, respectively. Heterosis for food:gain ratio from 2 to 7 weeks of age was -7.0%. 5. Crossbreeding of Mexican Creole birds with commercial type broilers might improve productive performance.

The effect of chaya (Cnidoscolus aconitifolius) leaf meal and of exogenous enzymes on amino acid digestibility in broilers.

1. The apparent ileal nitrogen (N) and amino acid digestibilities in chaya leaf meal (CLM) (Cnidoscolus aconitifolius) with added enzymes, and the same variables in diets containing different amounts of CLM were studied in chickens. 2. In the first experiment pectinase, beta-glucanase, and pectinase + beta-glucanase were added to CLM. In the second experiment, there were three diets based on maize and soybean: 0, 150 and 250 g/kg CLM. 3. Pectinase significantly increased both lysine and overall amino acid digestibilities in CLM. 4. In experiment 2, the amino acid digestibility in birds fed on CLM250 was lower than that from birds fed on either control or CLM150. Only the digestibilities of alanine, arginine and proline were lower in birds fed on CLM150 than in those fed on the control diet. Nitrogen digestibility was lower in birds fed on the CLM250 diet than on either control or CLM150 diets. These findings were attributed to the increasing concentration of fibre with increasing dietary CLM.

Performance of broilers fed on diets containing different amounts of chaya (Cnidoscolus aconitifolius) leaf meal.

The performance and gut measurements of broilers fed on diets containing different amounts of chaya (Cnidoscolus aconitifolius) leaf meal (CLM) were examined in two experiments. In the first experiment, 60 Hubbard chickens (30 males and 30 females; 2 weeks old) were fed on five maize diets; these were formulated using 0, 150 (CLM150), 250 (CLM250) or 350 (CLM350) g CLM/kg, and the fifth diet contained soyabean. In the second experiment, 148 Ross male chicks, 1 day old, were fed on three isonitrogenous and isoenergetic maize-soyabean-based diets, which included 0 (control), 150 (C150) or 250 (C250) g CLM/kg. The diets were offered ad libitum for 2 or 3 weeks in the first and second experiments, respectively. Food intake, weight gain and the food:weight gain ratio were recorded. The weight of the gizzard and intestine and the weight and length of the caeca were also determined in the second experiment. In experiment 1, the birds fed on the maize-soyabean diet had a higher (p < 0.05) weight gain and final weight than birds fed on maize only or on the CLM150 diets. There were no differences for any of the variables studied between the birds fed on the maize-soyabean diet and those fed on the CLM250, nor between males and females. In the second experiment, weight gain, food intake and the food:weight gain ratio for birds fed on C250 were lower (p < 0.05) than those in birds fed on either the control or C150 diets. The weights of the gizzard and intestine were the lowest and the highest, respectively, in birds fed on C250 (p < 0.05). The length and weight of the caecum from birds fed on the control diet were lower (p < 0.05) than those of birds fed on either the C150 or C250 diets. The results from this study suggest that CLM may be included up to 150 g/kg in commercial diets without having an adverse effect on poultry performance, and may also be mixed with maize up to 250 g/kg to improve the performance of chickens fed on low-protein diets.

True metabolisable energy, heat increment and net energy values of two high fibre foodstuffs in cockerels.

1. The yields of true metabolisable energy (TME) and net energy (NE) from chaya leaf meal and wheatfeed were mcasured in tube-fed cockerels. 2. TME, 5.76 MJ/kg, from chava leaf meal was lower than from wheatfeed, 8.39 MJ/kg. The total heat increment attributable to the feeding of chaya leaf meal was 1-7 times greater than that of wheatfeed. 3. The net efficiency of utilisation of ME (k) from chaya leaf meal was 0.64, while that from wheatfeed was 0.86. The role of different chemical composition, especially the high fibre content of the materials, is discussed. 4. The metabolisable energy and net energy values derived from chava leaf meal represented 0.34 and 0.23 respectively of its gross energy content. The combination of lower TME and lower net efficiency of utilisation led to chaya having a NE value, 3.86 MJ/kg, which was only 0.53 that of wheatfeed.