Journal of Livestock Science and Technology
Volume:9 Issue: 1, Jun 2021

An experiment was performed for evaluating calibration curve (CC) and comparing negative and positive controls (CNP) as a major method for estimating of phytase phosphorus equivalence for layer hens. Three hundred sixty 70-wk-old layer hens (W-36Hy-line) were used in a complete randomized design. Evaluated methods were setting the two regression equations for NPP-supplemented and phytase supplemented treatments with two sub-methods, include calibration curve (CC) or exclude phosphorus content of the basal diet (CC-BD) in calculation, and exploring enzyme equivalency by comparing phosphorus deficient diet as a negative and supplemented diet by inorganic phosphorus sources as a positive control group (CNP). Experiment included nine treatments (a phosphorus deficient basal diet contained 0.12% Av. P and 200, 300, 400 and 500 FTU/kg phytase was added to the basal diet, the rest four treatments were included basal diet supplemented with 0.20, 0.27, 0.35 and 0.43% Av. P). Each treatment in the experiment replicated five times, eight birds in each. Results indicated that methods of estimation had a significant effect on phosphorus equivalence estimation (p <0.0001). Fitted regression equations excluding P content of basal diet (CC-BD) estimated rational values than those ignore it (CC) (0.432% vs 0.564% for 500 FTU/kg phytase for layer hens) (p <0.0001). On average, among three methods used, CC method had the highest estimated values (p <0.0001). Regardless of mathematical method, there were no significant differences for egg production performance and egg quality traits served as response criteria (P˃0.05). In conclusion, the phosphorus equivalent value of enzyme varies according to the estimation methods. Hence, using matrix values of enzymes for accurate feed formulation depend on a variety of circumstances and decision making requires comprehensive information.

The effects of different sources of fiber in mash or pellet diets on growth performance and cecal microbial population of broiler chicken were studied for 42 days. The experimental design was completely randomized with 10 treatments arranged as a 2 × 5 factorial with 2 feed forms (mash vs. pelleted) and 5 diets consisted of 4 feeds containing 4 different fiber sources (i.e., sugar-beet pulp (SBP), wheat bran (WB), sunflower hull (SFH), all of which in 30 g/kg of diet and cellulose (CEL) in 5 g/kg of diet) and a control diet. The results showed that in the starter phase, all diets in pellet form results in a higher BWG of birds compared to those fed mashed forms of fiber sources and control diet (P < 0.05). Also, feed conversion ratio (FCR) was improved in birds offered diets contained fiber, except for SBP, in the pelleted form, compared to the birds fed fiber in mashed forms, in the starter phase (p <0.05). Birds fed pelleted diets containing WB and SFH had lower (P < 0.05) Coliforms and E. coli populations in the cecum, compared to the other treatments. Dietary inclusion of SFH and CEL in pellet form reduced blood TG. In summary, pelleting the diets contained WB, SFH, and CEL was more beneficial for improving FCR than the inclusion of SBP at starter phase. Also, the results suggest that the inclusion of 30 g/kg of natural fibers or 5 g/kg of CEL in the diets, based on corn-soybean meal, can improve the growth performance, with effects being more pronounced in pellet-fed birds than in mash-fed ones.

This study was conducted to evaluate the effect of feeding different levels of Pistachio pulp silage (PPS) on feed intake, nitrogen metabolism, protozoa population and purine derivative excretion in sheep. Experimental diets were different in amount of PPS. The compositions of diets given to the different treatments were as follow: (1) control (without PPS), (2) 7% PPS, (3) 14% PPS and (4) 21% PPS. Eight rams (40±2.5 kg) were used in a replicated Latin square design with four diets and four periods of 35 days each. Animals were fed with isocaloric and isonitrogenous diets. Feeding 14% of PPS enhanced significantly (p <0.05) dry matter intake, nitrogen intake and nitrogen retention in sheep. Purine derivatives excretion and so microbial protein synthesis increased (p <0.05) with adding PPS to experimental diets. Ruminal pH increased linearly with adding of PPS in this study. the Holotrich protozoa population decreased linearly by increasing level of PPS in diets (p <0.05). By increasing PPS in the experimental diets, total protozoa population and Entodinium sp., were changed quadratically (p <0.05). The highest number of protozoa population was related to 14% PPS in experimental diet. These results showed that PPS up to 14% can be used as proper source of feed for small ruminants to overcome the shortage of animal feedstuffs.

This study was conducted to evaluate chemical and mineral compositions, in vitro gas production (IVGP) and fermentation parameters, nutrient digestibility and rumen microbial enzymes activity of different parts of Moringa peregrina (MP) including leaves, stems and whole fodder compared to alfalfa hay (AH; four experimental treatments) using gas production (GP) technique. Leaves of MP had a higher crude protein (CP) than other fodder parts as well as AH. Content of neutral detergent fiber (NDF) in stems was higher than other experimental feed ingredients and it was comparable to AH. Highest and lowest non-fiber carbohydrates contents were observed in leaf part and AH, respectively. Regarding mineral contents, except for P and Fe which was highest in MP leaves, other minerals was highest in AH. Highest total GP and potential GP (b) was observed by stems incubation (p <0.05). However, in vitro dry matter (DM) and organic matter digestibility, metabolizable energy, microbial protein synthesis and ammonia-N concentration for MP leaves were higher than stem and AH (p <0.05). The highest and lowest DM and NDF two-stage disappearance rate was observed for MP leaves and stems, respectively (p <0.05). However, the highest and lowest carboxymethyl cellulase and microcrystalline cellulase activity were observed by incubation of MP stems and leaves, respectively (p <0.05). Activity of filter paper-degrading activity was unchanged among experimental feeds (P>0.05). Leaves of MP and alfalfa resulted in highest and lowest ruminal ɑ-amylase activity respectively (P>0.05). In conclusion, results indicated that different parts of MP fodder have potential nutritional value as alternative protein source for ruminant feeding, and leaves was also had higher nutritive value than other plant parts as well as AH.

This study was performed to investigate the effect of fermentation by Bacillus subtilis (B. subtilis) and Aspergillus niger (A. niger) and alkaline processing on the nutritional value and chemical composition of date palm kernels (DPK). DPK was fermented for 28 days under solid-state fermentation culture with two different microorganisms (B. subtilis and, or A. niger). Alkaline processing was performed by soaking DPK in NaOH solution for 24 hours. In this experiment, eight treatments were used: DPK (control), DPK fermented by B. subtilis, and A. niger separately or in combination, and processed with NaOH, alone or with B. subtilis or A. niger or both. Digestibility and gas production of fermented and processed DPK were performed using the batch culture and gas production techniques. The results showed that there was an increase in crude protein (CP) and a decrease in crude fiber concentrations due to the fermentation of DPK with B. subtilis and A. niger (P < 0.05). Total phenol content in fermented DPK (FDPK) with B. subtilis and A. niger was significantly lower than the control. Gas production significantly increased in FDPK compared to control and NaOH-treated samples (p <0.05). All treatments significantly increased the in vitro digestibility of DM (IVDOD) and OM (IVOMD) compared to the control (p < 0.01). Among the treatments, simultaneous fermentation of DPK with B. subtilis and A. niger had the most significant effect on increasing the microbial CP (MCP) and its efficiency (EMCP; p <0.01).

This study compared six non-linear equations [Exponential growth (4 parameters), Exponential growth (Stirling), Polynomial (Cubic), Quadratic, Brody, and Sinusoidal] for prediction of pre-weaning body weights at different ages in Holstein calves. Thirty-two calves (16 males and 16 females) were randomly divided into two treatment groups and fed with starter diets containing either corn or barley as the grain source. Starter feeding began on the third day of life, and high quality alfalfa hay and fresh cow milk were fed according to the farm schedule. The calves were weighed at birth and weekly thereafter until weaning. In this manner, ten weight records, including the birth and weaning weights, constituted the data set. The results of experiment revealed the fact that all functions mentioned earlier showed good fitness to predict weight gain in relation to age in all groups of calves. However, based on the goodness of the fit of various criteria and the statistical performance, the polynomial (cubic) function was considerably superior to other functions for predicting the calf live weight. The flexible growth functions (more parameters) very often give a closer fit to data points and a smaller residual sum of square (RSS) value than the simpler functions such as the Brody functions.

The objective of this study was to estimate genetic parameters for sexual dimorphism (SD) in birth weights (BW), weaning weights (WW), 6-month weight (W6), 9-month weight (W9) and 12-month weight (W12) of Baluchi sheep. Data were collected during 1981-2015 from Baluchi sheep flock (flock no 1) of Abbas Abad sheep breeding station located in Mashhad, Iran. Data were included 7339, 7303, 5884, 5162 and 4691 records of birth weight, weaning weight, 6-month weight, 9-month weight and 12-month weight, respectively. Six bivariate animal models were used to estimate variance components and corresponding genetic parameters in male and female lambs separately. The SD levels (ratio of Male/Female) increased from 1.06 at birth to 1.13 at yearling age. Except for W9 in which additive genetic variance and direct heritability (h_a^2) were greater in males, for the other studied traits, females experienced higher additive genetic variance and h_a^2. In both sex, maternal effects contributed significantly in phenotypic variation of body weights with greater contribution to body weights measured early in life. While in females, maternal genetic effect was greater than males, in males, maternal permanent environmental effect was greater which together with higher estimates of residual variances revealed greater sensitivity of male lambs to environmental conditions. Cross-sex additive genetic correlation (ra) was 0.86 for BW and 1.00 for the other studied traits. Maternal correlations between sexes were close to 1.00 indicating lack of sexual dimorphism for maternal effects on body weights of Baluchi lambs. Based on an approximate 95% confidence interval, the difference between sexes regarding direct heritability were not significant, indicating no need or opportunity for different selection strategies in two sexes. Therefore, a model including lambs of both sexes and with sex effects included in the model can be used for genetic evaluation.

In the present study data on growth traits of Moghani sheep breed, collected during 1988 to 2011 at Jafarabad breeding station, were used. The studied traits were average daily gain from birth to weaning (ADG1), average daily gain from weaning to six months of age (ADG2), average daily gain from six months of age to yearling age (ADG3), Kleiber ratio from birth to weaning (KR1), Kleiber ratio from weaning to six months of age (KR2), Kleiber ratio from six months of age to yearling age (KR3), growth efficiency from birth to weaning (GE1), growth efficiency from weaning to six months of age (GE2), and growth efficiency from six months of age to yearling age (GE3). Genetic and phenotypic parameters were estimated for autosomal and sex-linked components of the studied traits under animal model. Direct autosomal heritability estimates for ADG1, ADG2, ADG3, KR1, KR2, KR3, GE1, GE2 and GE3 were 0.09±0.01, 0.07±0.02, 0.03±0.01, 0.13±0.02, 0.09±0.02, 0.02±0.01, 0.07±0.01, 0.06±0.01 and 0.02±0.01, respectively. Pre-weaning studied traits were not influenced by sex-linked additive genetic components. Sex-linked heritability estimates for ADG2, KR2, GE2, ADG3, KR3 and GE3 were 0.04±0.01, 0.02±0.01, 0.02±0.01, 0.02±0.01, 0.02±0.01 and 0.03±0.01, respectively. Autosomal additive genetic correlations between the traits were ranged from -0.68±0.22 for ADG3-KR1 and ADG1-GE2 to 0.99±0.01 for KR3-GE3. Sex-linked additive genetic correlations among the traits were positive and varied from 0.14±0.02 for GE2-ADG3 to 0.98±0.01 for ADG3-KR3 and KR3-GE3. Results revealed that when sex-linked effects are important, genetic analysis using an animal model which accounts for both autosomal and sex-chromosome inheritance provides more accurate estimates of variance components of the studied post-weaning traits.