The objective of this study was to determine the effect of short-chain fatty acids (SCFAs; C4 powder) and medium-chain fatty acids (MCFAs; Bergaprime) on performance, carcass characteristics, and some serum parameters of broiler chickens. A total of 200 one-day-old male broiler chicks (Ross 308) were assigned to five dietary treatments, including control diets (C), C plus Virginiamycin (200 g/ton; ANTI) as positive control, C plus MCFAs supplement (1 kg Bergaprime/ton; M), C plus SCFAs supplement (3 kg C4 powder/ton in starter and 1.5 kg/ton in grower and finisher diets; S), and C plus the combination of SCFAs and MCFAs supplement (SM), as mentioned above according to a completely randomized design. Each treatment consisted of 4 replicates with 10 chicks each. There were no significant differences in body weight, feed intake and feed conversion ratio, and carcass traits among the treatments. SCFAs and MCFAs treatments had higher heterophil and lower lymphocyte percentage compared to the control treatment. Blood glucose and cholesterol concentrations were decreased in MCFAs and SCFAs (p < .05). Lipid percentage of thigh meat of MCFAs and SCFAs was decreased. These results indicated that dietary MCFAs and SCFAs positively decreased broiler chicken meat. ARTICLE HISTORY

AbstractThe present study evaluated the interaction effects of n-3 fatty acids (from linseed oil (LSO), 0 v. 2·5, % DM basis) with rumen undegradable:degradable protein (RUP:RDP) ratios (low ratio (LR) 27:73; high ratio (HR) 38:62 based on crude protein %) in dairy calves’ starter diet. Forty-eight 3-d-old female Holstein dairy calves (41·5 kg of body weight (BW)) were allocated in a 2 × 2 factorial arrangements in the following treatments (n 12 calves/each): (1) no supplementation of LSO with LR (NLSO-LR); (2) no supplementation of LSO with HR (NLSO-HR); (3) supplementation of LSO with LR (LSO-LR) and (4) supplementation of LSO with HR (LSO-HR). The calves were weaned on day 53 of the experiment and remained in the study until day 73. Intake was not affected by LSO and RUP:RDP ratio. However, average daily gain (ADG) was improved with LSO supplementation. Feeding the HR diet increased ADG compared with the LR diet during the entire period. Final BW was greater in calves fed on the LSO than those fed the NLSO diet. Microbial protein production did not differ among treatments. Calves fed on LSO diets had greater feed efficiency than those which were not fed on LSO diets. The calves supplemented with LSO had greater wither and hip heights compared with the unsupplemented calves. The glucose, cholesterol, HDL and insulin concentrations increased in calves supplemented with LSO. In conclusion, the HR diet improved calves’ performance post-weaning; however, LSO could enhance growth performance of dairy calves during the pre-weaning period.

This study investigated the effects of feeding dairy calves starter diets containing 19% or 22% crude protein (CP) content on a dry matter basis and either supplemented or not with soybean oil (SBO, 0 vs. 3%, dry matter basis) on growth performance, digestibility, urinary nitrogen, and purine derivatives (PD) excretion. A total of 48 female Holstein dairy calves (mean 39.8 kg of body weight) were randomly distributed to experimental diets in a 2 × 2 factorial arrangement of treatments. The 4 dietary treatments were (1) starter diet without SBO supplement and 19% CP (NSBO-19CP), (2) starter diet without SBO supplement and 22% CP (NSBO-22CP), (3) starter diet with 3% SBO and 19% CP (SBO-19CP), and (4) starter diet with 3% SBO and 22% CP (SBO-22CP). Milk feeding value was similarly based on a constant protocol across experimental treatments and calves had ad libitum access to water and starter diets throughout the study. All calves were weaned on d 63 of age and remained in the study until d 83 of age. Calves supplemented with SBO had lower starter feed intake and average daily gain (ADG) and lower feed efficiency (FE) but had a higher fecal score indicating a higher likelihood of diarrhea occurrence compared with unsupplemented calves. Wither heights, digestibilities of organic matter, CP, and neutral detergent fiber were decreased, and ruminal volatile fatty acids tended to be reduced, and the molar proportion of ruminal butyrate (preweaning) and acetate (postweaning) reduced by supplemental SBO. The urinary allantoin and total PD excretion were reduced; however, urinary nitrogen excretion was increased when calves were supplemented with SBO.The CP amount did not affect starter feed intake, FE, or diarrhea occurrence rate, whereas the 22CP diets increased neutral detergent fiber digestibility, improved ADG (tendency), and increased allantoin and urinary PD excretion compared with the 19CP diets. The starter feed intake, ADG, FE, diarrhea occurrence rate, nutrient digestibility, and ruminal fermentation were not affected by the interaction between starter SBO and CP level; however, hip height and total PD in calves that received the SBO-22CP diets were higher than those fed the SBO-19CP diets. In conclusion, based on our experimental conditions, supplemental SBO could not be recommended for dairy calves. Furthermore, our findings indicate that SBO has negative effects on performance more attributed to reducing starter intake, digestibility, and ruminal volatile fatty acid concentration rather than because of a limitation of starter metabolizable protein supply and intestinal amino acid availability. Therefore, our results indicate that feeding the higher starter CP content is not a viable strategy to compensate for the negative effects of SBO supplementation on the growth performance of dairy calves.

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This study aimed to investigate the effect of different levels of dietary threonine (i.e. 100%, 110% and 120% of Ross recommendations) and potassium (i.e. 0.85% and 0.94% of diet) on performance, immune response, and bone parameters broiler chickens. Three hundred one-day-old male broiler chickens (Ross 308) were randomly assigned to 1 of 6 dietary treatments in a completely randomized design with a 3 × 2 factorial arrangement. Growth performance was not affected by dietary treatments. Birds fed diet containing 120% threonine and high potassium level were exhibited a lower immune response to phytohemagglutinin-P (PHA-P) as compared to control group (P < .05). Addition of 120% threonine with 0.94% potassium decreased heterophil percentage and heterophil to lymphocyte ratio and increased lymphocyte percentage (P < .05). Tibia and femur width and ash, Ca and P percentage of tibia, and breaking strength of bones were not influenced by dietary potassium level, whereas the width of tibia and femur was increased in broiler chickens received diet containing 120% threonine and 0.94% potassium compared to control group (P < .05). It is concluded that broiler chickens FI during starter period, cell mediated immune response and blood hematology were influence by dietary threonine and potassium interaction.